Notes

Record Information

Source Institution:

University of Florida

Holding Location:

University of Florida

Rights Management:

The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.

The Division of Geology, of the State Board of Conservation, is
pleased to publish, as Florida Geological Survey Bulletin 48, a
study of the geology and hydrology of Jefferson County, Florida.
This report continues the series of coverage by county of the geo-
logic and economic resources of the State.
It is hoped that a complete coverage of the State will lead to
more comprehensive development of our mineral resources, par-
ticularly where these resources require large volumes and realize
a low sales price. Only if a large reserve can be shown to be present
in an area can such minerals be developed economically.

Respectfully yours,
Robert O. Vernon'
Director and State Geologist

Completed manuscript received
May 19, 1966
Published for the Florida Geological Survey
By The E. O. Painter Printing Company
DeLand, Florida

26 Hydrograph of well WJf-1N-4E-26 bb and a total monthly
precipitation graph of rainfall in Jefferson County, Florida .------- 86
27 Bar graphs showing chemical composition of artesian water
in Jefferson County, Florida -._-- -----._________--------. ---- 87
28 Hardness and total dissolved solids curve of artesian water
in Jefferson County, Florida -..-..._--... -...... ------------ 89

Gratitude is expressed to Dr. Robert O. Vernon for many
helpful suggestions and his efforts as State Geologist in making
this study possible. Appreciation is expressed to C. W. Hendry,
Jr., Assistant State Geologist, who gave freely of his time to
the writer both in discussion and field visits. The writer is
grateful to the staff of the Florida Geological Survey, who gave
immeasurable help in the various phases of the project. S. J.
Olsen, vertebrate paleontologist of the Florida Geological Survey,
generously wrote sections on vertebrate faunas for which the
writer is most appreciative.
Appreciation is expressed to Rowe Brothers Well Drilling Com-
pany and Terra-Rosa Hardware Company, Tallahassee, Florida,
and to Carr Well Drilling Company, Thomasville, Georgia, for fur-
nishing rock cuttings and other information on well drilling in
Jefferson County.
Special thanks are due L. H. Crampton, of the Tungsten
Plantation, Inc., for the many courtesies extended the writer.
The writer would like to express his appreciation to R. C.
Crooks, director of the Fertilizer Laboratory of the Chemical Divi-
sion, Florida Department of Agriculture, for providing chemical
data on the limestone samples submitted to his department for
analyses and to T. C. Bransford, Florida State Road Depart-
ment Testing and Materials Laboratory, for determining some
physical properties on limestone samples submitted to his depart-
ment.
The writer is grateful to the citizens of Jefferson County for
their many courtesies and aid during the course of the field work
for this report.
Mr. and Mrs. Paul Appin gave freely of their information con-
cerning the two deep oil tests in Jefferson County, and the writer
is grateful to them.
Sincere appreciation is expressed to William Clark and Nevin
Hoy of the United States Geological Survey for reading the manu-
script and making very useful comments.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

By
J. William Yon, Jr.

INTRODUCTION

PURPOSE AND SCOPE OF STUDY

The purpose of this report was to make a detailed study of the
geology of Jefferson County and to provide information needed
for development of the mineral resources of the area.
The field work was begun in the summer of 1961 and was
completed in the latter part of 1962. Where accessible, most of the
surface geology was mapped and cuttings from numerous wells
were examined for data on the subsurface geology. In conjunction
with the geological studies, a survey was made of the mineral
resources.

LOCATION OF AREA

Jefferson County is located in what is referred to as the Pan-
handle of Florida, as shown in figure 1. It bounds the State of
Georgia on the north; Leon and Wakulla counties on the west;
Taylor and Madison counties on the east; and the Gulf of Mexico
on the south. Jefferson County is wedge-shaped being approxi-
mately 25 miles wide along its northern boundary and 6 miles
wide along the southern boundary. The length of the county is 39
miles and it comprises an area of 598 square miles.

PREVIOUS INVESTIGATIONS

In many of the reports on the geology of Florida, reference is
made to Jefferson County. However, only those reports which are
countywide in aspect are mentioned below. Reports involving spe-
cifics of the county geology are indexed in the text where they have
direct bearing on some specific phase of the geology.
A report by Sellards (1917, p. 85-139) is a reconnaissance study
of the geology, mineral resources and springs of Jefferson County.
The general geology of Jefferson County is discussed by Mossom
(1926), Cooke and Mossom (1929), and Cooke (1945). The regional

2 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

i-r

!Monticello

Cox

5 R-
i 0

SE iE 7En

hw

Figure 1. Map showing location of Jefferson County, Florida.

work of Applin and Applin (1944, 1947, 1951, 1955) is a major
contribution to the understanding of the subsurface geology of
not only Jefferson County but all of Florida.

MAPS

The maps used for plotting the field data were United States
Geological Survey topographic maps, figure 2, and the Florida
State Road Department general highway map for Jefferson Coun-
ty. The base map used in this report was compiled from the topo-
graphic maps.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

SCALE

COUNTY
LOCATION

STATE OF FLORIDA
STATE BOARD OF CONSERVATION
JEFFERSON COUNTY
prepared by
DIVISION OF GEOLOGY /

Figure 2. Index to Topographic maps of Jefferson County, Florida.

4 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

TRANSPORTATION

Jefferson County is served by two railroads, the Seaboard Air
Line, and a branch line of the Atlantic Coast Line.
Three major highways traverse the county from west to east,
U. S. 27, 90, and 98. The two major north-south highways are
U. S. 19 and 221. Except for the southernmost part of the county
there are many secondary paved roads that make the county
accessible by car.

CLIMATE

Jefferson County is in an area of southeast wet continental and
north Florida transitional climate. It has an average January tem-
perature of about 57F, an average July temperature of about 82F
and 9 to 10 months frost free. The average annual precipitation
is 55 inches. Most of the rainfall occurs during the months of
June through September.

POPULATION AND INDUSTRY

The population in Jefferson County for 1950, 1956, and 1960
is shown on table 1. The population figures in 1950 and 1960 are
from the records of the U. S. Census Bureau, and the 1956 figure
is from estimates by the Bureau of Economics and Business Re-
search, University of Florida.

TABLE 1. Population of Jefferson County,
1950, 1956, and 1960

Percent change
1950 1956 1960 1950-60

10,413 9,200 9,543 -8.4

Agriculture is the principal industry of Jefferson County; it
has 190,000 acres in farms, and the farms average 342 acres.
The county is a large producer of pecans and watermelons. Cattle
raising, tung oil, and the dairy industry play an important role
in the economy of the county. The percent of total land in forest
is 73 percent or 248,000 acres.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

WELL AND OUTCROP NUMBERING SYSTEM

The well and outcrop numbering system used in this report is
based on the location of the well or outcrop and uses the rectangu-
lar system of section, township and range for identification. The
well or outcrop number consists of six parts: W for well or L for
outcrop, county abbreviation, the quarter/quarter location within
the section, the section, township, and range.
The basic rectangle is the township which is 6 miles square.
It is consecutively numbered by tiers both north and south of the
Florida base line and is also consecutively numbered east and
west of the principal meridian. In the present numbering system
the T will be left off the township number and the R off the range
number. Each township is divided equally into 36 square miles
called sections, and are numbered 1 through 36 as shown on figure
3. The sections are divided into quarters with the quarters being
labeled "a" through "d" as shown on figure 3. In turn, each of
these quarters are divided into quarters with these quarter/quarter
squares labeled "a" through "d."
An exception to the above system will be used for locations
occurring above the Watson Line near the Georgia-Florida State
line where irregular consecutively numbered sections are used and
will be listed only by the irregular section number.
When there is more than one well or outcrop in a quarter
quarter section they are identified by a sixth number at the end
of the fifth unit. The abbreviation used for counties in this report
are Jf for Jefferson, Ln for Leon, Md for Madison, Ty for Taylor
and Wk for Wakulla.

GEOLOGY

PHYSIOGRAPHY

INTRODUCTION

Cooke (1939, p. 14) divided Florida into the following five nat-
ural topographic regions: Coastal Lowlands, for all that area up
to 100 feet in elevation; Western Highlands; Marianna Lowlands;
Tallahassee Hills; and Central Highlands, for the generally higher,
hilly, interior regions.
Vernon (1951, p. 16) proposed a genetic classification in which
he recognized four of the following major physiographic divisions:

6 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

zu

S+ R3 E + R4 E R5 E R6E + R7E

I BASE LINE
/ WJF 1S-4E-2 bi

S I c- z
++ +a b

i + R3E +"Jr R4E R5E + R6E R 7 E

o 7 8 9 10 11 12
S 18 17 16 15 14 13
19 20 21 22 23 24

30 29 28 27 26 25

31 32 33 34 35 36

Figure 3. Well and Outcrop numbering system.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Delta Plain Highlands, Tertiary Highlands, Terraced Coastal Low-
lands, and River Valley Lowlands. He (Vernon, 1951, p. 16) also
stated that these major subdivisions could be further subdivided
into smaller units and local names applied to them.
Based on his idea of origin for the physiographic units of
Florida, Vernon (1951, p. 14, 16) made the following changes in
Cooke's (1939, p 14) terminology: Vernon replaced Cooke's Talla-
hassee Hills with Tertiary Highlands; included the Western High-
lands and Central Highlands in the Delta Plain Highlands; sub-
stituted Terraced Coastal Lowlands for Coastal Lowlands; and
River Valley Lowlands for Marianna Lowlands.
The Tertiary Highlands of Vernon (1951, p. 14, 16) include
sediments formed either as a part of a high-level, widespread,
aggradational delta plain, or of Tertiary sediments rising above
this plain. The lowlands were formed by marine erosion and depo-
sition along coastlines, stream erosion, and alluviation along stream
valleys.
In the latest work on the physiography of Florida, White, Ver-
non and Puri (Puri and Vernon, 1964, p. 7-15) divide Florida into
the following major groups: Coastal Lowlands, Intermediate
Coastal Lowlands, Gulf Coastal Lowlands, Central Highlands,
Northern Highlands, and the Marianna Lowlands. These primary
divisions are subdivided into secondary and tertiary physiographic
units.
The Northern Highlands extend across the northern part of
Florida from Trail Ridge on the east side of the State and then
westward to the Alabama state line (Puri and Vernon, 1964, p. 10).
They are continuous except where interrupted by the Marianna
Lowlands. The Northern Highlands are subdivided into the fol-
lowing secondary units: Trail Ridge, Florahome Valley, Tallahassee
Hills, Grand Ridge, New Hope Ridge, Washington County Out-
liers, and the Western Highlands.
White, Puri and Vernon (Vernon and Puri, 1964, p. 13, 14) pro-
posed three primary divisions to replace Vernon's Terraced Coastal
Lowlands, and they are: Coastal Lowlands, the Intermediate
Coastal Lowlands, and the Gulf Coastal Lowlands.
The deposits studied in this investigation lie within the East
Gulf Coastal Plain, a subdivision of the Coastal Plain Province
(Fenneman, 1938, p. 1-83). In Jefferson County the major phy-
siographic divisions of Vernon (1951, p. 16), White, Vernon,
and Puri are recognized, and include the following major
divisions, figure 4: (1) Tallahassee Hills, (2) Gulf Coastal Low-

lands, and (3) St. Marks, Wacissa and Aucilla River Valley Low-
lands. A Tertiary unit, the Woodville Karst Plain (Hendry and
Sproul, 1966) can be traced through Jefferson County.

NORTHERN HIGHLANDS

TALLAHASSEE HILLS

The term Tallahassee Hills includes the area lying between
the Florida-Georgia State line on the north, the Gulf Coastal Low-
lands on the south, the Withlacoochee River on the east, and the
Apalachicola River on the west. In Jefferson County the Talla-
hassee Hills includes the area extending southward from the
Florida-Georgia State line to the Gulf Coastal Lowlands.
The Tallahassee Hills are erosional-remnant hills and ridges
with elevations up to 260 feet. Along the eastern side of the county
there is a relatively large topographically low area associated with
a number of isolated hills. Although the Tallahassee Hills in this
area have been highly dissected by stream erosion and subsurface
solution, they probably once represented a nearly flat Miocene
delta plain that covered all of northern Jefferson County. The
Tallahassee Hills are composed of a heterogeneous mass of plastics
that comprise the Upper Miocene Miccosukee Formation and are
underlain by the Middle Miocene Hawthorn Formation, and the
Lower Miocene St. Marks Formation. 'Lake Miccosukee occurs
within the Tallahassee Hills in western Jefferson County, and in
many other places the Hills are interspersed with smaller lakes,
streams, and narrow valleys.
The Tallahassee Hills end in the southern part of Jefferson
County at a well defined southward-facing escarpment, figure 5,
named the Cody Scarp (Puri and Vernon, 1964, p. 11). In the
northeastern portion of Jefferson County the Aucilla River cuts
through the Tallahassee Hills. Where the Aucilla River forms
the county line boundary between Madison and Jefferson counties,
the Tallahassee Hills have been separated by erosion from their
counterpart to the east.

GULF COASTAL LOWLANDS

INTRODUCTION

The Pleistocene Epoch, or "Great Ice Age," is characterized by
worldwide fluctuations in sea level. The periods of time when sea
level was lowered are referred to as glacial stages. This was

10 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

**^ ^ ... . .

.3
1P': .....

Figure 5. View looking north towards the Cody Scarp in Jefferson County,
Florida.

accomplished by the storing of large quantities of ocean's water
as land-glaciers. The interglacial stages were those times when
the glaciers receded, thus returning the water to the seas and
causing a rise in sea level. During each of the interglacial stages,
when sea level rose and remained stationary at one elevation, a
terrace and shoreline was formed. According to Vernon (1951,
p. 36) the older and higher shorelines and terraces are preserved
because each succeeding rise in sea level during the interglacial
stages never reached the height of the preceding older stand of
the sea. Consequently, the record of the different sea levels during
the interglacial stages show a progressive decrease in elevations.
Cooke (1954, p. 248) recognized eight marine terraces and
shorelines in Florida. MacNeil (1950, p. 99) recognized only four
terraces and shorelines. Vernon (1951, p. 36-41) considered that
only four marine surfaces and shorelines exist in Florida. How-
ever, in a later report, Puri and Vernon (1959, p. 239-240), recog-
nized another shoreline for a total of five marine terraces and
shorelines.
Three marine terraces and shorelines are recognized in Jeffer-
son County, as shown in figure 6. The approximate altitude of the
shorelines and, tentative age are shown in table 2.
shorelines and~tentative age are shown in table 2.

The Gulf Coastal Lowlands in Jefferson County extend from
the Cody Scarp to the coastline and consists of the three Pleisto-
cene terraces and shorelines. The modern coast and submarine
plain is included under the Gulf Coastal Lowlands.

Modern Submarine Plain and Coastline

The present coastline of Jefferson County is a low or zero
energy shoreline (Price, 1953; Tanner, 1960). It is marshy, very
irregular, and is dissected by several streams that originate at
the inner edge of the coastal marshes. The absence of sand beaches
and barriers along the coastline is attributed to the lack of wave
activity and inadequate sand supply (Price, 1953; Tanner, 1960).
The modern submarine plain off the coast of Jefferson County
has a gentle seaward slope and the waters covering it are shallow.
In an attempt to determine the nature of the sediments on
the sea floor, the following methods were used to collect data:
sampled pinnacles which protrude above the surface of the water;
through the use of self-contained underwater breathing apparatus;
and evaluation of data obtained from the Corps of Engineers.
The data obtained from the first two methods indicated that the
submarine plain is a rock surface of silicified and dolomitized
Suwannee Limestone. Two of the features shown on the U.S.
Coast and Geodetic hydrograph 1261, the Grey Mare Rock and
Cobb Rocks, can readily be seen from a boat. The Grey Mare
Rock is a large pinnacle of silicified Suwannee Limestone, and
the Cobb Rocks are dolomitized Suwannee. The Corps of Engineers
prepared a bottom profile with logs of core borings along a proposed
intracoastal waterway from St. Marks to Tampa Bay, Florida.
(Survey Report of 1940, 1952, and 1956). Along the coast border-
ing Jefferson County the logs show that the rock surface is covered
by a thin veneer of clastics. Oyster bars are very prevalent along
the coast of Jefferson County, especially at the mouths of the
creeks and the Aucilla River.

12 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Silver Bluff Surface and Shoreline

The Silver Bluff shoreline is the term applied to a wave-cut
notch occurring at an elevation of 5 feet at Silver Bluff near
Miami (Parker and Cooke, 1944, p. 24).
The Silver Bluff shoreline was extended by MacNeil (1950, p.
104) to other parts of Florida and northern Georgia, and he con-
siders the toe of the Silver Bluff scarp to occur at an elevation
of 10 feet. As shown on the land-surface profiles (fig. 6), the small
escarpment whose toe occurs at an elevation of 8 to 10 feet is
considered to be the Silver Bluff strandline.
The Silver Bluff marine plain, the youngest and lowest of the
coastal terraces, extends from the edge of the present coastline
inward, four to six miles, to the 10-foot contour line, which marks
the base of a small escarpment.
The coastal marshlands forming the outer part of the Silver
Bluff marine plain consist of mud and silts that support grasses.
Inland from the coastal marsh belt is a fairly flat, poorly drained
sand area, with a prolific stand of cedar, palm, and pine trees.
Beneath the clastics is a shelf composed of Suwannee Limestone
which in places has been silicified or dolomitized. The formation
crops out through the sand cover in many places and in ditches
along logging roads.
The absence of barrier islands, the gentle slope of the Silver
Bluff marine plain, and the poorly developed escarpment seem to
indicate the coastline during Silver Bluff time was generally one
of low or zero energy, with a sparse supply of sand. However, the
feature shown on the physiographic map (fig. 4) along southwes-
tern Jefferson County may have formed as on offshore bar or shoal.

Pamlico Surface and Shoreline

The Pamlico shoreline and terrace is one of the best developed
Pleistocene features in Florida and can be recognized in most
areas of the State.
The Pamlico shoreline and escarpment can be seen in western
Jefferson County in the vicinity of Fanlew. The escarpment has
approximately 8 to 10 feet of relief, and its toe occurs at an
elevation of 26-30 feet. The Pamlico terrace covers the county
from the shoreline of the Silver Bluff terrace inland for a distance
of approximately 8 miles. The Pamlico terrace has formed a lime-
stone plain that is covered by varying thicknesses of sands and
clays. The Wacissa River flows across the terrace and gives rise

to a broad swamp area along its course. In eastern Jefferson County
the Pamlico terrace is fairly well drained, but to the west the
drainage is poor and swamps are more prevalent. Palmetto, scrub
oak, hardwood, and pine trees are very common on this surface.
Calico Hill, a sand ridge with about 12 feet of relief and lying
parallel to the Wacissa River, is probably a Pamlico dune (fig. 4).
Inland from the Pamlico shoreline, in eastern Jefferson County,
are found a series of crescent-shaped features which are believed
to be sand dunes that have relief up to 20 feet. Outcrops of the
St. Marks Formation and the Suwannee Limestone occur on the
lower part of the terrace near the Silver Bluff shoreline. Mont-
morillonitic clays, containing weathered mollusk shells, were
found at localities LJf-2S-3E-14-ac and LJf-2S-3E-15-center and
are believed to have been deposited during Pamlico time.
A portion of the Pamlico shoreline, as shown in figure 6, was
drawn by using recognizable escarpments. However, for the most
part, the 30-foot contour was used to show the approximate posi-
tion of the Pamlico shoreline.

Wicomico Surface and Shoreline

Cooke (1945, p. 281-286) places the shoreline for the Wicomico
from 100-105 feet.
The Wicomico shoreline is believed to coincide with the Cody
Scarp, whose base occurs at 40-45 feet, cutting across the southern
part of Jefferson County. However, when the escarpment is traced
westward into Leon County it rises to 100 feet and higher (C. W.
Hendry, Jr. Personal Communication). This anomaly in elevation
of an apparently similarly related feature is not uncommon in
Florida where limestone lies near the ground surface and is readily
susceptible to solution (White, 1958, p. 9-44). Yon and Puri (1962,
p. 679-680) point out that the Wicomico shoreline in Gilchrist
County, Florida, occurred at 70 feet because it had been lowered
by solution of the underlying limestones. The Wicomico terrace
in Jefferson County includes all of the area lying between the
Pamlico shoreline and the Cody Scarp. The Wicomico marine plain
extends across the width of the county and is approximately 4 to
5 miles wide, except on the western edge of Jefferson County where
it becomes about 7 miles wide.
The Wicomico terrace deposits consist essentially of sands and
clayey sands that have been deposited on top of a limestone shelf.
The surface is generally poorly drained and swampy, especially on
the flood plains of the Wacissa and St. Marks rivers. The western

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

side of the terrace contains a belt of sand dunes formed during
the stand of the Pamlico seas.
An area of sandhills, covered with vegetation, with elevations
160 feet and higher, occurs inland from the Wicomico shoreline
in Western Jefferson County and are interspersed with sinkhole
lakes. It is believed these sand hills are Wicomico age deposits.

WOODVILLE KARST PLAIN

C. W. Hendry, Jr. (Personal Communication) proposes the term
Woodville Karst Plain for a low, gently sloping plain beginning in
the southern part of Leon County and extending southward
through Wakulla County to the Gulf. He describes the plain as
being characterized by sand dunes lying upon a limestone surface.
The porous nature of the sands has readily permitted ground
water to percolate downward, thereby causing dissolution of the
limestone. The result of this solution has lead to a continuous and
rapid lowering of the original surface. The area is characterized
by the formation of shallow sand-bottom sinkholes. The Woodville
Karst Plain extends into Jefferson County, and includes all the
area mapped as the Gulf Coastal Lowlands (fig. 4).
The Woodville Karst Plain is not generally as well developed
in Jefferson County as it is in Leon and Wakulla counties. The
dune belt in northwestern Jefferson County best exhibits the
characteristics of the Woodville Karst Plain as described by
Hendry. The dunes appear to be barchan type with up to 20 feet
of relief and are underlain by Miocene and Oligocene limestones
that are soluble in percolating acidized water. Because of the
collapse of the limestone, shallow sinkhole development is fairly
prevalent.

RIVER VALLEY LOWLANDS

INTRODUCTION

The River Valley Lowlands consist of all the valleys in Jefferson
County. A number of creeks originate within the Tallahassee
Hills and flow into the St. Marks and Aucilla rivers. Most of them
are laden with humic acids, are high in color, and carry very little
sediment.
The Aucilla River forms part of the eastern boundary of
Jefferson County and is the largest stream in the county. The St.

16 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Marks River has its headwaters in Leon County, and only flows
a few miles through Jefferson County.
The Wacissa River originates from a group of springs just
below the town of Wacissa and flows southward into the Aucilla
River.
The Penhook River heads up in the swamps occurring on the
Pamlico surface and flows southward across the Coastal Marsh
Belt into the Gulf.
A number of creeks originate at the head of the Coastal Marsh
Belt in the lower part of Jefferson County and flow southward into
the Gulf.

AUCILLA RIVER VALLEY LOWLANDS

The Aucilla River has its headwaters in Brooks County,
Georgia, and flows southward along the eastern edge of Jefferson
County to the Gulf of Mexico. From the Georgia-Florida State line
southward to where U. S. Highway 90 crosses the Aucilla, the
river flows in a valley approximately 1-mile wide that has been
cut into Miccosukee and Hawthorn clastics. At times the Aucilla
is almost dry, as shown in figure 7. However, during periods of high
rainfall, the river overflows the small channel and broadens out to
cover the entire valley, giving it the appearance of a lake. During
periods of high water the main channel is not distinguishable, and
swamp conditions are prevalent along the upper course. Why the
valley of the Aucilla is considerably wider in the upper reaches
than in the lower reaches presents an interesting problem. The
configuration of the bedrock, figure 8, the reasonable closeness of
the underlying rock to the land surface, and the narrow channel
of the present stream occupying the broad valley, may point
toward solution of the underlying limestone and subsequent col-
lapse of the overlying sediments as an origin for the valley.
However, it is possible that during higher stands of the Pleistocene
seas, the valley was formed by progressive downward cutting of
the stream as sea level fell.
To ascertain if river terraces occurred along the Aucilla River
in the Tallahassee Hills area, a number of land-surface profiles
compiled from topographic maps were drawn normal to the river's
axis. Two stream-cut terraces above the flood plain of the Aucilla
River show up in the profiles at approximately 10 and 40 feet.
Higher fluvial surfaces may be present but erosion has altered
the land surface to a degree that they are no longer apparent.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Figure 7. Aucilla River at low water stage in Jefferson County, Florida.

From where the Tallahassee Hills join the Gulf Coastal Low-
lands the Aucilla River flows in a steep-walled valley cut into the
Suwannee Limestone. Rapids flowing over silicified limestone are
common. Terraces do not appear to have been formed along this
section of the river. The flood plain is narrow, and during flood
stage the river flows out over the surrounding area. From the
point where State Highway 257 crosses the river to the point
where the Aucilla disappears underground, outcrops of dolomitized
Suwannee Limestone are almost continuous. From a point in
section 21, T3S, R4E to Nutall Rise the river flows underground.
The Aucilla River is joined by the Wacissa River in the vicinity
of Nutall Rise, and flows on a southerly course to the Gulf. Springs
are present along the Aucilla River southward from Nutall Rise
to the Gulf of Mexico.
According to the Surface Water Branch, United States Geologi-
cal Survey, the Aucilla River has an approximate drainage area
of 740 square miles in Florida, which would include most of Jeffer-
son County, almost half of Madison County, and a small portion
of Taylor County.
Gum Creek, Wolf Creek, Beasleys Creek, and Jones Mill Creek
and many others are tributary to the Aucilla River.

17

18 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

WACISSA RIVER VALLEY LOWLANDS

The Wacissa River's origin is a series of springs near the town
of Wacissa in Jefferson County. The river is fairly shallow with
rapids along its course, and flows across the Gulf Coastal Lowlands
in a channel cut into Suwannee Limestone and the St. Marks
Formation. The flood plain of the river is 1 to 3 miles wide and
although ill-defined in some areas, it is distinguishable as swamps
on aerial photographs. Stream terraces are not visible along the
river's valley.
Near the confluence of the Wacissa and Aucilla rivers, the
Wacissa becomes a multichanneled stream. Observation of aerial
photographs shows that the bends in the river seem to indicate
that some of these channels are oriented with northwest-southeast,
and northeast-southwest linear trends. It is also possible that the
bedrock is dolomitized or silicified and offering considerable resis-
tance to erosion; consequently, the stream, in seeking zones of less
resistance has formed multichannels. The water is clear in the
upper reaches of the Wacissa because the source is springs, but
in the lower reaches it becomes charged with humic acid waters
from the swamps, and is high in color.
Welaunee and Cow creeks are tributary to the Wacissa River.

ST. MARKS RIVER VALLEY LOWLANDS

The St. Marks River has its headwaters in Leon County and
only flows a few miles through Jefferson County. The river is
sluggish and flows in a valley approximately a mile wide. Along
most of its course swampy conditions prevail, and the river water
is charged with humic acids giving it a high color. The course of
the river in Jefferson County seems to be somewhat controlled
by the dunes. The Cody Quadrangle map shows that the river
has a meandering course that is oriented with dune development.
In the area where the St. Marks leaves Jefferson County the flood
plain of the river is very swampy and difficult to delineate.
Tributary to the St. Marks are Burnt Mill Creek (enters the
St. Marks in Leon County), Sweetwater and Moore branches.
Sellards (1910, p. 61) believed that a stream flowed through
what is now Lake Miccosukee basin into the St. Marks River.
He also stated that Lloyd Creek during periods of excessive runoff
emptied into the St. Marks River.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

LAKES

Sellards (1910, p. 47-76) published significant information on
lakes in Florida. He discussed lakes in the State that were peculiar
in character and manner of development. He concluded that most
of the shallow lakes in Florida, which included Lake Miccosukee in
Jefferson County, were originally stream channels that have been
lowered by solution, and greatly enlarged laterally by the formation
of sinkholes. He noted that as each new sink formed, the older
sinks became clogged and partially filled with sediments washed
into them from the lake basins in which they occur.
White (1958, p. 66-73) believes that most of Florida's shallow
lakes are the result of solution along the surface of the underlying
limestone caused by lateral movement of the ground water over
the soluble limestone. The depth that solution takes place is
controlled by the depth at which the lateral movement of the
ground-water table occurs. White (1958, p. 66-73) further states
that basin excavation by sinks might be the reason why the water
in the lake basins has disappeared, rather than why the lakes
have formed.
Lake Miccosukee, located in the Tallahassee Hills province, is
irregular in shape with an area of about 5,000 acres. Located near
the north end of the lake is a sinkhole, which has been ringed
by an earthen dam to prevent the sinkhole from draining water
from the lake. Wards Creek which enters the southeast end of
the lake is an intermittent stream that only supplies water to the
lake basin during periods of high runoff. The main source of water'
for the lake is from rainfall in the immediate area. The growth
of aquatic vegetation is so prolific in parts of the lake that boat
travel is restricted to channels cut through the vegetation.
When the water level of the lake is normal or above its normal
stage, surface flow occurs through an outlet in the southern part
of the lake. Northeast of Lloyd a series of sinkholes lie along the
course of the drain and captures much of the water. According
to Sellards (1910, p. 61):

"Lake Miccosukee probably represents a basin developed by
solution near the headwaters of streams originally tributary
to St. Marks River. Previous to the formation of Miccosukee
Basin the drainage of this part of the county doubtless
passed through small streams, to the south past the present
village of Lloyds, then to the Gulf through the St. Marks
River."

20 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

The bedrock map, figure 8, indicates that Lake Miccosukee
overlies a basin in the limestone. It appears from the available
data that the Miocene St. Marks Formation is missing, and the
basin is formed in the Oligocene Suwannee Limestone.
The piezometric surface in the area around Lake Miccosukee
is 40 to 60 feet above mean sea level, and 20 to 40 feet below the
lake surface. Consequently, ground-water recharge is taking
place through the sinkholes in the lake region.

SPRINGS

The springs that form the headwaters of the Wacissa River
are discussed by Ferguson and others (1947, p. 88-91), and except
for the measurements made on Big Spring and Blue Spring on
December 7, 1960, they state:

WACISSA SPRINGS AT WACISSA

"Location-The group of springs known as Wacissa Springs
are located 1 mile south of the town of Wacissa.
Description-These springs comprise the headwaters of Wacis-
sa River and are located within 0.8 mile of the head of the
Wacissa River.
Wacissa Springs are composed of the following springs: Big
Spring, Garner Springs, Blue Spring, Buzzard Log Springs, Min-
now Spring, Cassidy Spring, two apparently unnamed springs
herein designated as No. 1 and No. 2, Thomas Spring, and Log
Springs.

BIG SPRING

Big Spring, sometimes known as Big Blue Spring, consists of
a circular pool approximately 90 feet in diameter. Having a cavity
about 70 feet in diameter whose side walls drop almost vertically
to a depth of about 40 feet. The cavity is in limestone which appears
to be cavernous on both the east and west sides. Soundings indicate
a maximum depth of 45 feet. The bottom of the pool is covered
with a layer of silt approximately one foot in depth. The average
depth of the pool away from the cavity varies from 2 to 5 feet.
The spring flow discharges into two runs, one flowing southwest
and the other flowing northwest, both entering the Wacissa River
within 0.2 mile of each other. The runs are full of eel grass and
measurements of the discharge are made very difficult. The run

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

G E O R G I

-- 1 0 1 2 3 4 5 MILES
SCALE

o
/

*\~ 4
C'
3

of ~IEX.
c6te

EXPLANATION

STATE BOARD of CONSERVATION

prepared by DIVISION of GEOLOGY

Figure 8. Contours showing approximate altitude of the top of the first
limestone in Jefferson County, Florida.

A

A OUTCROP
o WELL OR CORE HOLE
io ALTITUDE IN FEET, OF TOP
OF FIRST LIMESTONE
REFERRED TO MEAN SEA LEVEL
L10- LINE, IN FEET, REFERRED TO
MEAN SEA LEVEL
CONTOUR INTERVAL 20 FEET
AREA WHERE ST MARKS IS
FIRST LIMESTONE PENETRATED
IIIIII AREAWHERE SUWANNEE IS
FIRST LIMESTONE PENETRATED

21

22 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

flowing northwest is approximately 0.2 mile in length and 80 feet
in width, the dimensions of the other were not determined.

GARNER SPRINGS

Garner Springs consists of two headpools. In the smaller a
limestone cavity, 8 feet in diameter, has a maximum depth of
6.3 feet. It was impracticable to get to the larger of the spring-
heads because its outlet channel was obstructed by fallen trees.
This spring run is approximately 800 feet long and 50 feet in
width and is full of eel grass and other aquatic growth.

BLUE SPRING

Blue Spring consists of a circular pool with a limestone cavity
about 40 feet in diameter, which has a maximum depth of 19.0
feet. The spring run is about 900 feet long and approximately
50 feet in width. The run is full of eel grass and aquatic vegeta-
tion and the surface has a scum of "duck seed."

BUZZARD LOG SPRINGS

Buzzard Log Springs consists of four springheads, two being
at the confluence of the run with the Wacissa River and the other
two at the head of the run which is approximately 0.2 mile in
length. The maximum depth of the two spring cavities at the
mouth of the run was 8.1 feet and the flow emerges from limestone
in one and apparently from a sand boil in the other. It was imprac-
ticable to get to the head of the run due to the stream being
obstructed by logs. The run is covered with "duck seed" and is
full of aquatic growth.

MINNOW SPRING

Minnow Spring consists of a circular pool with a limestone cavi-
ty about 15 feet in diameter in the bottom at a maximum depth of
8.1 feet. The water in the boil of the spring is filled with sand
particles flushed out of the cave. The run is approximately 100
feet in length and flows in an easternly direction.

CASSIDY SPRING

Cassidy Spring consists of a pool with a limestone cavity at the
bottom 8 feet in diameter and in a maximum of 28.0 feet of water.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

The run is approximately 70 feet long and discharges into the
Wacissa River.

SPRING NO. 1

Spring No. 1 consists of a cavity in a limestone outcrop within
the Wacissa River. The maximum depth of the pool cavity was
24.7 feet.

SPRING NO. 2

Spring No. 2 discharges from a circular cavity in a limestone
outcrop beneath a maximum of 18.9 feet of water in the Wacissa
River.

THOMAS SPRING

Thomas Spring discharges from a limestone cavity approxi-
mately 8 feet in diameter under the Wacissa River at a maximum
depth of 28.2 feet.

LOG SPRINGS

Log Springs discharges from two cavitiies within a limestone
pool 40. feet in length by 15 feet in width. The maximum depths
to the floors of the cavities are 28.2 feet and 24.0 feet, respectively.
Sand Spring boils are visible at many points along the stretch
of the river from Teate's fish camp to the head of the Wacissa
River. There are believed to be additional springs upstream from
Thomas Spring, downstream from the mouth of Big Spring Run
and also in Little River. These were not investigated.

DISCHARGE

The following measurements of discharges were made on July
16, 1942:

BIG SPRING

Big Spring-The total discharge was found to be 69.4 (64.5
second-feet total, Dec. 7, 1960) second-feet which was comprised
of a discharge of 22.7 cfs (15 mgd) in the southwest run, and
46.7 cfs (30 mgd) in the northwest run or a total of 41.7 mgd
on December 7, 1960.

The springs are intact in their natural surroundings. A group
of men at one time were said to have been interested in developing
the springs as an attraction for tourists but the plan never mater-
ialized. The river in the vicinity of Springs No. 1 and No. 2 is used
for swimming. The runs of the various springs are frequented
by fishermen, owing to the abundance of fish.

OTHER SPRINGS

Walker Spring, also in Jefferson County, is 8 miles southeast
of Lamont."

LINEAR TRENDS

Vernon (1951, p. 47) recognized faulting and extensive frac-
ture patterns in Florida. The fracture patterns were mapped on
the basis of their physiographic expression, as shown on mosaics
of aerial photographs.
In Citrus and Levy counties (Vernon, 1951, p. 47) the axis
of the Ocala uplift is paralleled by regional fractures trending
northwest-southeast, exactly marking the crest of the anticline.
A secondary system crosses the primary system at large angles and

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

trends northeast-southwest. According to Vernon (1951, p. 48)
the northwest plunge of the Ocala uplift extends through Madison
County into Jefferson County.
Examination of a mosaic of aerial photographs of Jefferson
County shows that northeast-southwest and northwest-southeast
linear trends exist in the county, as shown in figure 9. The multi-
channels of the Wacissa River in its lower reaches may be the
result of the stream following fractures in the Suwannee limestone.
Certain portions of the Aucilla River also seem to be following
linear trends. The lack of subsurface control and surface ex-
posures makes it difficult to determine whether or not all the map
lineations represent fractures. However, fractures do exist in the
county because the writer observed a large one in the limestone at a
spring near the headwaters of the Wacissa River. The trend of the
fracture was northeast-southwest. This particular fracture was not
seen as a distinct lineation on the aerial mosaic but as figure 9
shows, a northeast-southwest linear zone passes just north of the
headwaters of the Wicassa River, to which it may be related. The
structure map showing the configuration of the top of the Suwan-
nee Limestone, as shown in figure 10, indicates that a northwest
slope of a Suwannee high almost parallels the northeast-southwest
linear trend mentioned above. Observation of the bedrock map (fig.
8) shows that the St. Marks does not reflect the slope that occurs
within the underlying Suwannee positive area thus, apparently,
ruling out a surface fault. It may mean, however, that the linea-
tion is a fracture that extends through the Miocene clastics over-
lying the limestones of the St. Marks Formation and the Suwannee
Limestone.

STRATIGRAPHY

INTRODUCTION

The sediments that occur in Jefferson County range in age from
Paleozoic to Recent. The Suwannee Limestone (Oligocene) is
the oldest rock exposed in the area, and the deposits laid down
during the Recent are the youngest. Table 3 is a list of the
geologic formations that occur in Jefferson County.
Most of the subsurface data discussed in this report was ob-
tained from studying well cuttings, and core samples, figure 11.
Data on the age of rock older than late Eocene was from two oil
exploratory wells. The discussion of the older sediments encoun-

tered in these two wells will be generalized, and, for the most
part is taken from other sources.
Table 4 lists wells in Jefferson County from which geologic
data was obtained.
Jefferson County lies within or near a zone of facies change
and, so that a better understanding of how the county fits in with
the general stratigraphy of Florida, the following statement of
Applin and Applin is cited (1944, p. 1679-80):

"Beds from the top of the Oligocene to the base of the
late middle Eocene are a continuous limestone sequence
throughout the area, whereas two sedimentary or deposi-
tional faces are recognized in Florida and Southern Georgia,
in each stratigraphic unit between the top of the early

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

R3E + R4E + R5E E R6E

G E O R G

R3 E 4- R4E -- R5E

STATE OF FLORIDA
STATE BOARD OF CONSERVATION
JEFFERSON COUNTY
prpdred by
DIVISION OF GEOLOGY

R6E R7E

Figure 11. Well locations and lines of sections in Jefferson County, Florida.

middle Eocene and the base of beds of Austin age (Upper
Cretaceous). On the one hand, west Florida and southern
Georgia are occupied by a elastic facies which is similar in
its broader aspects to the sediments of the western Gulf
Coastal Plain and is composed largely of sand and shale with
some limestone and chalky marl. On the other hand, over
most of the peninsula, the sedimentary section is almost
continuous limestone from the top of the Oligocene into the
Lower Cretaceous, giving a known thickness for this facies
of more than 10,000 feet in southern Florida. Anhydrite and
gypsum are present in this facies from late middle Eocene
to Paleocene and also in the limestone of the Lower Cretace-
ous, but little has been noted in the Upper Cretaceous units.
Thin streaks of carbonaceous shale and lignite are found in
the central part of the peninsula in the limestone facies of
the middle Eocene. In northern Florida and in the north
quarter or north third of the peninsula, the limestone and
plastic facies grade laterally into each other. In general,
with the passage of time, the limestone of the peninsula
encroaches upon the elastic facies, spreading northward in
successive stages, so that by the end of early middle Eocene
the limestone facies occupies all of the peninsula, northern
Florida, and southern Georgia. In general also, the fora-
miniferal microfaunas of the elastic facies resemble those
present in formations in the western Gulf Coast, whereas
the microfaunas of the limestone facies in the peninsula
from the top of the early middle Eocene to the top of the
beds of Taylor age resemble those of Cuba, the West Indies,
Mexico, and Europe, with only a few species present that are
known in other places in the United States. Species of
ostracods and bryozoans show a like dissimilarity with those
found in western faunas. Beginning with the top of the
beds of Taylor age in the peninsula, the more familiar Gulf
Coast microfaunas again appear. Some mingling of faunas
of the two facies has been noted in a few wells in north
Florida in the early middle and lower Eocene, but none in
Paleocene or late Upper Cretaceous. The fauna of the Lower
Cretaceous limestones of southern Florida again resembles
that found in certain derived deposits in Cuba and also that
of the El Abra limestone of southern Mexico (Cenomanian-
Albian) there designated as Middle Cretaceous."

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

PALEOZOIC ERA

ORDOVICIAN (?) SYSTEM

According to Applin (1951, p. 23), Coastal Petroleum Company,
E. P. Larsh No. 1, penetrated Paleozoic quartzitic sandstone at a
depth of 7,909 feet. He assigned it to the Lower Ordovician (?)
undifferentiated, but stated that only 4 feet of these sediments
were penetrated and could be a boulder in the lower part of the
Mesozic (personal communication, August, 1963).

MESOZOIC ERA

TRIASSIC SYSTEM

Newark (?) Group

Varicolored shales and sands of Triassic Age were reported
by Applin (1951, p. 10-26) in the Coastal Petroleum Company,
E. P. Larsh No. 1 test well at a depth of 6,800 feet. Near the base
of the well, from 7,850 to 7,890 feet, volcanic diabase sills or dikes
are associated with these plastic rocks of Triassic (?) Age, (Applin,
1957, p. 1489). Applin (personal communication August 1, 1963)
now refers the above sediments to the Upper Triassic (?) Newark
(?) Group, and also lowered the top of the Triassic beds to 7,030
(?) feet.

CRETACEOUS SYSTEM

Comanche Series

The two deep oil tests drilled in Jefferson County penetrated
beds of the Comanche Series. These beds consist of varicolored
shales interbedded with quartz sands and limestone.
The Comanche Series was penetrated in the Coastal Petroleum
Company, E. P. Larsh No. 1 test well, located in the NW1/4SE1/4
sec. 1, T2S, R3E, at the depth of 3,875 feet (Applin, personal
communication Aug 1, 1963), and the Southern States Oil Corpora-
tion test well, located in the SW4SW1/, Sec. 17, T2N, R5E, at
3,800 (?) feet. The thickness of the Comanche Series in the
Coastal-Larsh well is 3,155 feet.

34 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Gulf Series

Studies made by Applin and Applin (1944, 1947) and the
Southeastern Geological Society Mesozoic Committee (1949)
placed the Upper Cretaceous sediments occurring in Jefferson
County in the Gulf Series. According to these reports, Jefferson
County lies within or near the zone where the carbonate facies
of peninsular Florida meet the Clastic facies of western Florida.
The Gulf Series in Jefferson County, from oldest to youngest
beds, consists of the Atkinson Formation, beds of Austin Age. and
beds of Taylor Age.

ATKINSON FORMATION

The Applins (1947) introduced the name Atkinson Formation
for those subsurface sediments occurring in Alabama, Georgia,
and north Florida that lie between the top of the Lower Cretaceous
and the base of the beds of Austin Age. On the basis of differences
in lithology, they divided the Atkinson into three unnamed mem-
bers (upper, middle, and lower) and also recognized two
microfaunal groups within the Atkinson Formation. The upper
member carries a fauna closely related to that of the Eagleford
shale in Texas and the middle and lower members contain a fauna
similar to that of the Woodbine Sand in Texas. On the basis of
this faunal difference The Southeastern Geological Society Mesozoic
Committee (September, 1949) divided the Atkinson Formation
into an "A" zone, which contains the Eagleford fauna, and a "B"
zone, which contains the Woodbine fauna. To facilitate the
correlation of the Atkinson Formation of the southeastern gulf
region with the Eagleford and Woodbine Formations of Texas,
Esther R. Applin (1955, p. 1511) redefined the Atkinson to consist
of two members; an upper member, of Eagleford Age, and a lower
member of Woodbine Age. The lower member includes the middle
and lower members as originally defined by Applin (1947).
According to Paul L. Applin (personal communication August 1,
1963) in the Southern States Oil Corporation, Millard and Gossard
No. 1, ". . the sandy beds in the lower part of the lower Atkinson
are absent, and the 'marine shale' (formerly called middle
Atkinson) rests unconformably on the Comanche Series." The top
of the upper member of the Atkinson occurs from 3,410 (?) to
3,655 (?) feet, and the lower member is encountered from 3,665
(?) to 3,800 (?) feet in the Southern States well, thus giving the
formation a total thickness of 390 feet. Lithologically the upper

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

member is brownish to greenish gray shale, interbedded with some
fine grained glauconitic sandstone containing microfossils and
molluscan shell fragments. The lower member is primarily a dark
gray microfossiliferous shale.
The upper and lower members of the Atkinson Formation are
present in the Coastal Petroleum, E. P. Larsh No. 1 oil test well.
The upper member occurs from 3,400 to 3,700 feet, and is a
greenish gray and gray calcareous sandy shale; and a greenish gray
to gray, fine to medium glauconitic quartz sand. The upper member
is characterized for the foraminifers Planulina eaglefordensis,
Valvulineria infreqeuns, Gumbelina moremai, Gumbelina reussi,
Globigerina cretacea, and Trochammina wickendeni. The lower
member of the Atkinson is encountered from 3,700 to 3,875 feet
(Applin, personal communication, August 1, 1963) and is a gray
to gray-green glauconitic, fine to medium, quartz sand; and a gray
to dark gray sandy shale. The foraminifers Ammobaculities braun-
steini, Ammobaculites comprimatus, Ammobaculites advenus, Am-
mobaculites plummerae, and Trochammina rainwater characterize
the lower member.

BEDS OF AUSTIN AGE

Beds of Austin age occur from the depth of 3,268 to 3,410 (?)
feet in the Southern States Oil Corporation oil test well, and the
formation consists of gray, chalky, microfossiliferous limestone,
gray calcareous shale, brown-speckled shale, and hard gray marl
(Applin and Applin, 1944, p.1472-73). The lithology of the Austin
beds occurring in the Coastal-Larsh oil test are similar to those
described above in the Southern States Oil Corporation well, and
range in depth from 2,890 to 3,400 feet.

BEDS OF TAYLOR AGE

The upper beds of Taylor Age are missing in the Southern
States Oil Corporation oil test well, and the first penetration is
in beds of lower Taylor Age at 3,056 feet, (Applin and Applin, 1944,
p. 1711). In the southern part of Jefferson County, in the Coastal-
Larsh No. 1 oil test, beds of Taylor Age occur in the interval-
2,890 to 3,400 feet. Lithologically the Taylor is composed of gray
chalk, and a gray calcareous microfossiliferous shale containing
Inoceramus fragments.

36 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

CENOZOIC ERA

TERTIARY SYSTEM

Paleocene Series

BEDS OF MIDWAY AGE

The Applins (1944, p. 1703) recognized beds in the Tallahassee
area containing a microfauna similar to the foraminifers found
in the Tamesi (Velasco) of Mexico. They consider this faunal
unit a part of the Midway Group. In the Southern States Oil
Corporation oil test well, located in Jefferson County, this fauna
occurs from 2,490 feet to approximately 3,056 feet (Applin and
Applin, 1944, p. 1706). In the southern part of Jefferson County,
the writer also found the Tamesi fauna in the Coastal Petroleum
Co., Larsh No. 1 oil test well in the intervals-2,510 to 2,560 feet.
The lithology of this unit is a dark gray, very calcareous, slightly
glauconitic, clay containing abundant microfossils.

Eocene Series

WILCOX UNDIFFERENTIATED

In the Southern States Oil Corporation, oil test well, Applin and
Applin (1944, p. 1701) designated a plastic interval of fine to very
fine grained, glauconitic and microfossiliferous quartz sand
occurring between 2,223 and 2,490? feet as Wilcox Stage. This
determination was on the basis of several species of Globigerina
and Globorotalia, and Globototalia wilcoxensis Cushman.

CLAIBORNE STAGE

LAKE CITY LIMESTONE

The Lake City Limestone was proposed by Applin and Applin
(1944, p. 1693) for a limestone faces of early middle Eocene
occurring in north Florida and peninsular Florida.
The Lake City Limestone in Jefferson County consists of
cream to light brown, slightly peat flecked, medium hard,
limestone (calcarenite). It is gypsiferous, glauconitic, cherty,
microfossiliferous and has moderate to good porosity. In the
Southern States Oil Corporation oil test well, the Lake City
Limestone was encountered from 1,740 to 2,223 feet, a thickness

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

of 483 feet (Applin and Applin, 1944, p. 1695). In the Coastal-
Larsh well the Lake City is from 970 to 1,820 feet, a thickness of
850 feet. The foraminifer Dictyoconus americanus is a principal
fossil guide to the Lake City Limestone, and occurs in abundance
in the Larsh well.

AVON PARK LIMESTONE
The Avon Park Limestone was proposed by Applin and Applin
(1944, p. 1686) for the upper part of late middle Eocene deposits
found in a well at the Avon Park Bombing Range, Polk County,
Florida. Florida Geological Survey well No. W-668 was designated
as the type well.
The Avon Park Limestone in Jefferson County is a very pale
orange, medium hard, moderately porous, gypsiferous, microfos-
siliferous, cherty, partially recrystallized to crystalline limestone
(calcarenite). Near the bottom of the Avon Park, the sediments
became peat flecked and dolomitized. In the Southern States Oil
Corporation well the Avon Park Limestone occurs from 880 to
1,740 feet, a thickness of 860 feet. The complete Avon Park
Limestone interval in the Coastal-E. P. Larsh No. 1 test well is
unknown because of a sample gap from 160 to 925 feet.

OCALA GROUP

For historical review of the term Ocala prior to 1957, Florida
Geological Survey Bulletin 38 is cited as a reference. Puri (1957,
p. 22-24) redefined the Ocala Limestone and raised it to the rank
of group and subdivided it into three formations which are in
ascending order: The Inglis Formation, the Williston Formation,
and the Crystal River Formation.

INGLIS FORMATION
The Moodys Branch Formation, consisting of two members,
the Inglis and Williston, was proposed by Vernon (1951, p. 115-
116) for basal sediments of late Eocene age in Florida. Puri (1957,
p. 24) later raised the Inglis Member to the rank of formation.
The Inglis Formation in Jefferson County is a tan, soft to
medium hard, moderately porous, gypsiferous, microfossiliferous,
partially dolomitized, crystalline limestone (calcarenite). In the
vicinity of Monticello the top of the formation occurs at 780 feet
and the base at 880 feet, a thickness of 100 feet.

38 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

WILLISTON FORMATION
The Williston member was proposed by Vernon (1951, p. 141)
for about 30 feet of foraminiferal limestone overlying the Inglis
member of the Moodys Branch Formation. The Williston member
was raised to the rank of formation by Puri (1957, p. 28-29).
The Williston Formation occurs from 705-780 feet, a thickness
of 75 feet in a well near Monticello. Lithologically, the Williston
Formation is a pale orange, moderately porous, microfossiliferous,
crystalline to partially recrystallized limestone (calcarenite).

CRYSTAL RIVER FORMATION
Puri (1953, p. 130) proposed the Crystal River Formation to
replace Vernon's Ocala limestone (restricted). The type locality
of the Crystal River Formation is in the Crystal River Rock
Company quarry, Citrus County, Florida, where 108 feet of lime-
stone is exposed.
The Crystal River Formation primarily consists of a pale
orange, soft to medium hard, good to moderately porous, microfos-
siliferous, partially recrystallized limestone (calcarenite). In some
instances it is a calcirudite because of the large number of
Lepidocyclina specimens. In the vicinity of Monticello the Crystal
River Formation is 205 feet thick and occurs from 500 to 705 feet.

Oligocene Series

VICKSBURG GROUP

SUWANNEE LIMESTONE

History.-Cooke and Mansfield (1936) applied the name Suwannee
Limestone to the fossiliferous limestones cropping out along the
Suwannee River from White Springs to Ellaville. The history of
the stratigraphic nomenclature of the Suwannee Limestone has
been adequately discussed in Florida Geological Survey Bulletins
21 and 29, and are cited as very good references for historical
information.
Distribution.-The Suwannee Limestone is the oldest rock crop-
ping out in Jefferson County and the area of outcrop is shown on
the geologic map (Plate 1). It extends from the Wakulla-Jefferson
County lines eastward along the edge of secs. 31 and 32, T3S, R3E,
for about 2 miles before turning northward and intersecting U. S.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Figure 12. Dolomitized Suwannee Limestone cropping out on the bank of
the Aucilla River, Jefferson County, Florida.

Highway 98 on the east side of Gum Creek. From U. S. Highway
98 the outcrop pattern continues northward, almost parallels State
Highway 59, and finally merges with the Cody Scarp (fig. 5) north
of the town of Wacissa. The Suwannee Limestone, in many areas,
is covered by a thin veneer of Pleistocene sand. However, from
just below Lamont to just north of Nutall Rise, it is almost
continually exposed along the banks of the Aucilla River either
as silicified boulders, or as massive dolomite beds, figure 12. Both
the dolomite beds and the silicified boulders often form rapids
along the river, figure 13.
The Suwannee Limestone is exposed in the bed of the Wacissa
River from just below its headwaters near the town of Wacissa
to the confluence with the Aucilla River, just above Nutall Rise.
North of Cody Scarp the formation is covered by younger deposits.
However, a few outcrops have been observed, such as the outcrop
of silicified Suwannee Limestone occurring on the rim of a sinkhole
lake on sec. 32, T3N, R6E, and at a locality LJf-1S-5E-12-bb
located north of Lamont. As shown in the geologic cross sections,
figure 14, the Suwannee is continuous over all of Jefferson County
and in many places is the first bedrock encountered. Silicified or

39

40 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Figure 13. Rapids on the Aucilla River caused by dolomitized Suwannee
Limestone, Jefferson County, Florida.

dolomitized Suwannee Limestone forms the bottom of the Gulf
of Mexico off Jefferson County, shown in figure 15.
General Lithology.-The Suwannee Limestone is a marine lime-
stone consisting of a partially recrystallized limestone (calcare-
nite). It is very pale orange, finely crystalline, weakly cemented
with CaCO3, with moderate to good porosity, and very fossiliferous.
Chemically, it will approach 97 percent CaCO,.
Silicified limestones are very common in the outcrop area in
the form of boulders, shown in figure 16. In some cases the top of
the formation is silicified in the subsurface. Examination of well
cuttings indicates dolomitization of the limestone has also occurred
in the subsurface at different depths and in the outcrop area,
especially along the Aucilla River.
A lithology different from that at the type locality of the
Suwannee Limestone was noted from cuttings and cores for several
wells in the county. It is a limestone (calcirudite) characterized
by Lepidocyclina specimens. Generally, most of the microfauna is
so poorly preserved, they are difficult to identify. In core hole
WJf-1N-5E-25-ca, near Aucilla, a Lepidocyclina horizon was

NORTH

Correction to Vertical Scale on Section A-t,.
Elevation should be moved down one Interval. SOUTH
Sea Level is at the -40 interval.

Figure 15. Dolomitized Suwannee Limestone exposed in the Gulf of Mexico
off the coast of Jefferson County, Florida.

encountered and according to Cole (personal communication, April,
1964), the Lepidocyclinas are Lepidocyclina (Lepidocyclina)
mantelli and Lepidocyclina (Eulepidina) undosa and this section
could be correlated in time with the Oligocene Marianna Limestone.

Thickness.-The exact thickness of the Suwannee has not been de-
termined in Jefferson County because most of the information
available is from wells that terminate in the Suwannee. However,
in the previously mentioned Southern States Oil Corporation'oil
test, 336 feet of the Suwannee Limestone was penetrated and quite
likely represents the formation's maximum thickness.

Stratigraphic Relationships.-The Suwannee Limestone lies un-
conformably upon the Crystal River Formation and unconform-
ably underlies the St. Marks or Hawthorn Formations. Where the
St. Marks and Hawthorn Formations are absent, it underlies the
younger Miccosukee Formation. Below the Cody Scarp the Suwan-

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Figure 16. Silicified boulders of Suwannee Limestone exposed in roadcuts
in southern part of Jefferson County, Florida.

nee is covered unconformably by Pleistocene deposits and scattered
outliers of the Hawthorn Formation.
Fauna.-The echinoids Cassidulus gouldii (Bouve) and Clypeaster
rogersi (Morton) were identified from the Suwannee Limestone
in the outcrop area. The foraminifers Coskinolina floridana Cole,
Discorinopsis gunteri Cole, and Rotalia mexicana Nutall were
identified from outcrops as well as well cuttings.
Geologic Exposures.-The Suwannee Limestone is at or near the
surface in most of the southern half of Jefferson County.
The best exposure of the Suwannee Limestone in Jefferson
County is present at locality LJf-3S-4E-28-da on the south face
of an active quarry. The following section was measured at this
locality, figure 17:

On the north face of the quarry there are hard
ledges formed, and in the base of the quarry a hard
dark brown dolomite is exposed. Adjacent to the
north side of the quarry there are a series of caves,
sinks, and natural bridges.

The following are localities where the formation can be seen
exposed in the bed of the Wacissa River or in the banks of the
Aucilla River:

1. LJf-2S-5E-29 dc: Six-tenths of a mile north of the bridge
on State Highway 257 on the east bank of the Aucilla
River. Just above rapids formed by silicified Suwannee
about 4 feet of partially recrystallized limestone (calcare-
nite), very pale orange, finely crystalline, becoming deeply
weathered with blue-green clay and streaks of chert forming
in the rock.
2. LJf-2S-5E-22 aa: On the west bank of the Aucilla River,
2 feet of partially recrystallized limestone (calcarenite),
containing molds of microfossils.
3. LJf-2S-3E-2 bd: 10 feet below water level on Wacissa River,
is a crystalline limestone (calcarenite), containing molds of
microfossils.
4. LJf-2S-3E-13 da: Exposed in the bed of the Wacissa River
is a partially recrystallized microfossiliferous limestone
(calcarenite).
Approximately 3 miles northeast of Lamont at locality LJf-
1S-5E-12 bb, 4 feet of Suwannee Limestone is exposed in an
inactive quarry that was dug around the year 1909.
A number of exposures of Suwannee sediments are present
in the southern part of the outcrop area just north and to the
south of U. S. Highway 98. The following localities are represen-
tative:

45

46 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

1. LJf-4S-3E-16 ab: In a ditch beside a timber road.
2. LJf-4S-3E-17 bb: In a ditch beside a timber road.
3. LJf-3S-3E-27 dd: In a ditch beside a timber road.
4. LJf-4S-3E-22 ba: On the bank of the Penhook River.
5. LJf-4S-3E-15 cb: On the bank of the Penhook River.
As shown on the geologic map (Plate 1), numerous localities
of silicified Suwannee Limestone are present throughout the
county. Perhaps the most impressive evidence of silicification of
the limestone is at the Big Blue Spring on the Wacissa River,
where about 45 feet of silicified Suwannee Limestone is exposed
in a vertical section. Because of the silicification of the Suwannee
Limestone many rapids are present on the Aucilla River.
Dolomitization of the Suwannee can be observed at many
localities in the outcrop area, and many dolomite boulders, exposed
by construction, are present along U. S. Highway 98 beginning
in sec. 2, T4S, R3E, and continuing to the Aucilla River. Dolomitiz-
ation is also very prevalent along the Aucilla River and the
following localities are cited:

1. LJf-3S-4E-2 cb: Four feet exposed on east bank of Aucilla
River.
2. LJf-3S-4E-10 cc: Eight feet exposed on west bank of Aucilla
River.
3. LJf-3S-4E-28 db: Ten feet exposed in one of a series of sinks
about three-quarters of a mile from where the Aucilla River
goes underground.

Miocene Series

TAMPA STAGE

ST. MARKS FORMATION

History.-The sediments assigned to the Lower Miocene have been
sub-divided and redefined many times since the name Tampa was
first applied to those deposits by L. C. Johnson (1888, p. 235). The
latest revision was made by Puri (1953, p. 17). He places all
sediments previously called the Tampa Formation in the Tampa
Stage. He divided the Tampa Stage into the St. Marks and
Chattahoochee Formations. In the present report, the writer will
adhere to the nomenclature presented by Puri.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Distribution.-As shown in Plate 1, the St. Marks sediments do not
occur all over Jefferson County, but are confined to two separate
areas. The largest area is irregularly shaped and occurs in over half
of the northwestern and central parts of the county. A smaller
area of St. Marks sediments occur in an oblong shaped region
in southwestern Jefferson County. Outcrops of St. Marks are
rare as the greater part of the deposits are covered by younger
sediments. The exposures of the St. Marks that were observed
occur in sinkholes, ditches and stream valleys. As shown by cross
sections A-A' and C-C' (fig. 14), the St. Marks Formation is
absent in part of the county.

General Lithology.-The St. Marks Formation is a white to very
pale orange, finely crystalline, sandy, silty, clayey, limestone (cal-
cilutite). It has poor to moderate porosity, contains molluscan
casts, and few species of foraminifers. The calcilutite has been
partially dolomitized and silicified in the outcrop area and in the
subsurface. In the outcrop area, located in the lower southwestern
part of the county, and in core holes WJf-1S-3E-13-aa and WJf-1S-
4E-29-db the St. Marks is a partially recrystallized limestone
(calcilutite). It is very pale orange, very sandy, finely crystalline,
with poor porosity. This lithology is incorporated with a pale
yellowish brown, sandy, cryptocrystalline, microfossiliferous,
partially dolomitized limestone (calcilutite), with poor to moderate
porosity. These two calcilutites are similar to the intraformational
conglomerates reported by Hendry and Yon (1958, p. 28) in the
Jim Woodruff Dam area.

Thickness.-As shown by the geologic cross sections in figure 14,
the thickness of the St. Marks is variable. Geologic cross section
A-A' indicates that the accumulation of the St. Marks sediments in
the large basin on the western side of Jefferson County approaches
a thickness of 90 feet. Section B-B' (fig. 14), in the northern part
of the county, shows the thickness is variable. However, in core
hole WJf-3N-3E-36-ca the St. Marks is 120 feet thick and this
is the greatest noted accumulation of St. Marks sediments in the
county. Section C-C' (fig. 14) shows that the St. Marks sediments
become very thin or absent on the outer edges of the Suwannee
basin in the central portion of the county. Section D-D' shows
that 20 to 35 feet of St. Marks accumulated in a Suwannee
Limestone basin, but to the east the formation is missing.

48 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Stratigraphic Relationships.-The St. Marks unconformably
overlies the Suwannee Limestone and is overlain unconformably
by the Hawthorn Formation. In the southwestern part of the
county, St. Marks deposits are covered unconformably by the
Miccosukee Formation. It appears from the elevation of the St.
Marks sediments in the Monticello area that at one time these
sediments covered most of Jefferson County. However, during or
prior to Hawthorn deposition, the sediments were extensively
eroded and removed from a large expanse of the area.

Fauna.-The microfossils in the St. Marks Formation have not
been fully described, but Sorites sp. and Archaias floridanus are
two common species that are readily identifiable in St. Marks
deposits.
The Mollusca in the Tampa Stage sediments have been
described by Dall (1890, 1915) and Mansfield (1937).

Geologic Exposures.-As shown on the geologic map (Plate 1), the
St. Marks Formation can be seen cropping out in the ditches along
U.S. Highway 98 from the Wakulla County line eastward for 21/2
miles to Gum Creek. It is also exposed for about 2 miles in the
ditches beside a north-south road that almost parallels the Wakulla-
Jefferson County lines in secs. 19 and 30, T3S, R3E.
The thickest exposure of St. Marks beds is at locality LJf-154
located in the southeast corner of Land Lot 154, Monticello NE
quadrangle. The following section was measured on the north
side of a sinkhole:

Many exposures of St. Marks Formation were observed on
Lloyd Creek north of the town of Lloyd. The following description
is of samples taken on the west face of Lake Drain sink (locality
LJf-1N-3E-11-dd) located on Lloyd Creek:

Approximately 26 feet of St. Marks Formation was observed
at Horseshoe Spring, one of the several springs at the headwaters
of the Wacissa River.

ALUM BLUFF STAGE

HAWTHORN FORMATION

History.-The term Hawthorn Formation was proposed by Dall and
Harris (1892, p. 107) for deposits exposed at Hawthorne, Florida.
(For a good historical review of the term Hawthorn, the reader
is referred to Florida Geological Survey Bulletin 29). Puri (1953,
p. 38, 39) described the formation as a lithofacies of the Middle
Miocene Alum Bluff Stage. Puri and Vernon (1959, p. 120) later
cited Brooks Sink, Bradford County, as a cotype locality of the
Hawthorn Formation. Vernon (1951, p. 187) used the term
Hawthorn Formation to include all Middle Miocene marine beds
in peninsular Florida.
In the past, the Hawthorn Formation in Jefferson County
included all Miocene beds younger than the St. Marks Formation.
However, during the course of working well samples and observing
the surface outcrops, it became apparent that the sediments
contained phosphate and the "mineral" phosphorite. As these
phosphatic beds covered most of the county and seemed to correlate
with the sediments Vernon defined as Hawthorn in the peninsula,
this horizon will be separated from the overyling section of
heterogeneous non phosphatic clastics and only the lower section
containing phosphate will be considered as the Middle Miocene
Hawthorn Formation.

Distribution.-The Hawthorn Formation is present in the
subsurface over most of Jefferson County north of the Cody Scarp.
Much of the Hawthorn outcrop pattern shown on the geologic
map was not observed in the field. A contour map was drawn on
top of the Hawthorn Formation, and where the Hawthorn surface
was higher or equal to the ground surface the formation was
considered to be at or close to the ground surface. In theory the
Hawthorn should be visible in these areas which are generally
confined to stream valleys and low areas. However, in most
instances the formation is covered by slump and is not visible.
Outcrops were observed on Lloyd Creek and the Cascades near the

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

town of Lloyd. Except for two outcrops observed on the Aucilla
River the formation appears to be missing in the southern part
of the county.

General Lithology.-The Hawthorn Formation consists of pale
olive, light greenish gray, yellowish gray, light gray, and moderate
yellow, sandy, waxy, phosphatic clay. The clay contains
phosphorite grains and is interbedded with very fine to medium,
some coarse, clayey quartz sands that also contain phosphorite.
In some instances, the clays and sands are cherty, and are also
associated with thin sandy calcilutite stringers.

Thickness.-The geologic section B-B' (fig. 14) indicates that in
the northern part of the county the top of the Hawthorn Formation
is irregular, and the thickness has been reduced by erosion. Section
A-A' (fig. 14) shows that the Hawthorn Formation in central and
southern Jefferson County reaches a thickness of 50 to 70 feet.
On the eastern side of Jefferson County as shown in cross section
C-C' (fig. 14) the Hawthorn appears to have been deposited in
a basin and attains a thickness of about 240 feet.
At a sinkhole called the Cascades, 51 feet of Hawthorn sedi-
ments are exposed and this is the thickest outcrop of the Hawthorn
observed in Jefferson County.

Stratigraphic Relationships.-The Hawthorn Formation lies
unconformably upon the St. Marks Formation or the Oligocene
Suwannee Limestone.
The type of contact between the Miccosukee Formation and
the Hawthorn is not known. However, available data indicates
the two units may be conformable. Where the Miccosukee For-
mation is absent, the Hawthorn deposits are overlain unconform-
ably by Pleistocene sands.

Fauna.-The fauna in the Hawthorn deposits consists of rare
sharks teeth and very rare species of the foraminifers Streblus
beccarii, Globigerina bulloides and Elphidium species. Oyster
shells were observed eroded from the bank of Lloyd Creek just
south of the bridge on State Highway 158.

Geologic Exposures.-The thickest exposure of Hawthorn deposits
is at the Cascades (locality LJf-1N13E-22-bd). The following
section was measured on the northwest wall of the sink:

Exposures of Hawthorn were observed along the Aucilla River
at the following localities:
1. LJf-1S-5E-27 bb: On east bank of Aucilla River, 4 feet of
light gray, very sandy, phosphoritic clay.
2. LJf-2S-5E-29 dc: On east bank of Aucilla River, 2 feet of
light gray, fine to medium, angular to subangular, clayey,
phosphoritic, quartz sand.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Exposures of nonphosphoritic sediments observed along Lloyd
Creek are assigned to the Hawthorn Formation because of their
stratigraphic position and because lithologically they are similar
to the Hawthorn beds exposed at the Cascades.

CHOCTAWHATCHEE STAGE

MICCOSUKEE FORMATION

History.-The Miccosukee Formation is composed of a heterogene-
ous complex of sediments that was referred to the Lafayette
Formation (Pliocene) by Matson and Clapp (1909).
Sellards (1917, p. 96-110) referred the sediments of the
Lafayette Formation to the lower Miocene Alum Bluff Formation.
Later Gardner (1926, p. 1-2) raised the Alum Bluff Formation to
the rank of group. Mossom (1926, p. 184) placed the Alum Bluff
Formation as mapped by Sellards in the Chipola Formation of the
Alum Bluff Group (Middle Miocene).
Cooke and Mossom (1929, p. 77-125) included these sediments
in the Hawthorn Formation (Middle Miocene) and considered the
Hawthorn Formation an equivalent of the Alum Bluff Group as
mapped by Gardner.
Vernon (1951) recognized the complex of deltaic sediments as
a delta of "Hawthorn age."
Doering (1960, p. 182-189) assigned these sediments to the
Plio-Pleistocene Citronelle Formation.
Puri and Vernon (1964) reported all pro-deltaic Upper Miocene
sediments as the "Miccosukee formation." The name "Miccosukee
formation"was taken from preliminary copies of the manuscripts
of Yon's Jefferson County and Hendry's Leon County geological
reports.
Puri and Vernon (1959) pointed up the need for a detailed
survey of the surficial sediments in north Florida that would
determine the source of the deposits, the nature of their deposition,
and their geologic age.
In the independent investigations of the geology of Jefferson
County, Florida, by J. W. Yon, Jr. and of Leon County, Florida,
by C. W. Hendry, Jr., cuttings from approximately 200 water wells
and 15 core holes and outcrops were examined. The surface
deposits in the Tallahassee Hills area of Jefferson and Leon
counties represent an upper elastic unit that is deltaic in origin,
as pointed out by previous investigators, and unconformably
overlie a lower marine plastic unit. The deltaic unit caps the hills

54 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

and high level flats, whereas the marine plastics occupy the lower
inter-hill areas, though these lower areas are in part rolling
topography as well. The gross lithologies of each unit are distinctly
different; however, this difference is frequently not readily
apparent in single exposures. The upper unit can be mapped
across Jefferson and Leon counties, Florida, and in adjacent
counties. This unit is herein formally named the Miccosukee
Formation by Hendry and Yon (1967, In press).

Definition and Distribution.-In Jefferson County the Miccosukee
Formation includes all deposits in the Tallahassee Hills area that
lie above the Middle Miocene Hawthorn Formation.
The Miccosukee covers all of Jefferson County from the Cody
Scarp (Plate 1) northward to the Georgia State line. The absence
of these plastics south of the escarpment, indicates that the
Miccosukee was never deposited or was thin and subsequently
removed by Pleistocene marine erosion.
The geographic limits of Miccosukee Formation are not yet
adequately known. However, in addition to Jefferson County it is
present to the west in Leon and Gadsden counties and extends
eastward into Madison County. The Miccosukee is a heterogeneous
unit with physical features that are characteristic of deltaic
deposits, such as channel cut and fill, irregular and variable bedding
in the vertical sections, lenticular deposits of sand and clay,
crossbedded sands, interbedding of montmorillonitic and kaolinitic
clays and alluvial sands, and the presence of land vertebrates.
These above features substantiate Vernon's theory (1951) that
the deposits from Tallahassee eastward are part of a large deltaic
mass. Vernon also postulates that this deltaic mass wedges out
to the east.

General Lithology.-The Miccosukee, in outcrops and in subsur-
face samples is an assemblage of lenticular clayey sands and clay
beds which individually can be traced laterally for only short
distances. In general, the formation consists of moderately sorted
to poorly sorted, coarse to fine grained, varicolored, clayey, quartz
sand; and montmorillonitic, kaolinitic, varicolored, sandy clays.
Quite frequently the sands are crossbedded, and also contain
crossbedded thin laminae of white to light gray clay. The clay
laminae are associated with sands of two different grain sizes;
that is, very fine to medium size, figure 18, and very fine to very
coarse size, figure 19. Vernon Taylor (written communication,
1963) stated the X-ray diffraction patterns indicate that the

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

laminae associated with both quartz sands is kaolinite. The sands
containing the clay laminae are the most widespread and generally
the most persistent characteristics of these deposits and always
occur at the top of the unit. In general the Miccosukee is
heterogeneous in nature and, as already mentioned, no two
outcrops exhibit the same pattern of deposition. However, this
in itself makes these deposits very distinctive. The sediments in
many places are deeply weathered laterites, and the weathered
profile is often 10 to 15 feet deep, which gives the outcrops a
massive appearance. However, bedding undoubtedly was once
present, but has been obliterated by the intense weathering.

Thickness.-As shown on the geologic cross section C-C', (fig. 14)
the Miccosukee has a thickness up to 160 feet. The cross sections
show the surface of the plastics to be very irregular and probably
represents an eroded surface. However, the cross sections indicate
that the top of some of the highest hills approach the same
elevations and probably nearly represent the original depositional
surface.

Stratigraphic Relationships.-In northeastern Jefferson County,
the Miccosukee Formation lies unconformably upon the St. Marks
Formation. The contact between the Miccosukee Formation and
the underlying Hawthorn Formation in Jefferson County may be
conformable because of a transition from marine to deltaic
sediments with no loss in the record. Regional correlations will
be necessary to determine the stratigraphic relationships of this
unit with the known upper and middle Miocene beds to the east
of Jefferson County.
In southwestern Jefferson County, Pleistocene sands overlie
the Miccosukee unconformably.

Fauna-At locality LJf-2N-6E-l-dd teeth were found that have
been described by Olsen (1963, p. 308-314) as molars from the horse
Merychippus sp. and rhinoceros Diceratherium sp. Olsen (1963)
compared the Jefferson County horse teeth with a larger series
of Tertiary horses from the western United States They agreed
most closely with Merychippus from pre-Valantine (Early
Pliocene) and post-lower Snake Creek (Upper Miocene) beds.
However, the material was too fragmentary for more than a
generic determination.
According to Olsen (1963) the single molar of the rhinoceros
Diceratherium sp. is not the same as those of the genus from the

Middle Miocene of western United States. He (Olsen, 1933)
concludes this is expected from an animal that occurs in a slightly
higher stratigraphic horizon.
Olsen (1963) further states:
"A new species, Merychippus gunteri was described by
Simpson (1930) from a fullers earth pit of lower Middle
Miocene age at Midway, Florida, some 50 miles to the west
of the Jefferson County locality: In the same paper, Simpson
also recorded another species, M. westoni from the Middle
Miocene of Newberry, Florida, 85 miles to the south of the
locality under discussion. The Merychippus teeth from
Jefferson County do not belong to either of these two
species."

Geologic Exposures.-The Miccosukee Formation can be observed
in roadcuts throughout the area. The sediments are so variable

58 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

that at any given outcrop you might observe individual features
or sequence of beds that are different from any other outcrop.
However, as already stated, the fact that the sediments are variable
on a local scale makes them mappable on a gross scale. The
following outcrops are cited to give some idea of the nature of the
sediments:

Locality LJf-3N-5E-31 aa: Roadcut on the east side of U. S.
Highway 19, about 3.1 miles south of the Georgia-Florida
State line. The sediments in this section illustrate the rapid
sedimentation changes and channel cut and fill of a deltaic
environment. This section is the type locality of the
Miccosukee Formation.

Unit Description Variable
thickness (feet)

C Mottled yellow brown, red brown, and
greenish gray, very fine to medium, some
coarse, angular to subangular, clayey, quartz
sand, cemented firmly with clay and iron
oxide, contains thin laminae of white clay
that apparently dip northward under unit
B, these crossbedded laminae are most
noticeable near the contact of Unit C with B,
top of Unit C becomes a deeply weathered
red color (rust).
Near the contact of Unit C and B the
sand at the base of Unit C becomes fine to
coarse and angular to subrounded, predomi-
nately coarse grained; there is no sharp
contact between Unit C and B except that
they weather differently, also near the
contact of the units the color in Unit C
becomes a mottled purple red and greenish
gray, with large gray spots up to 6 inches in
diameter. Northward along the roadcut
Unit C occurs again. However, here the color
is more a light yellow brown, with some
mottled red and greenish gray color; this
part of the unit contains crossbedded

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

laminae that apparently dip southward
under Unit B. The sand is coarse grained
in this part of the unit near the contact of
Unit C and A (clay bed), and has 2-inch
joints filled with greenish gray clay. These
joints have good relief because limonite
cemented sands border their outside edges
and hold them up. The sediments on the
extreme northern end of this roadcut are
believed to belong to Unit C, but are a deeply
weathered red color and all bedding
characteristics are destroyed -_-----
B Mottled purplish red, red brown, yellow
brown, and greenish gray, very fine to
medium, some coarse, angular to subangular,
quartz sand more clayey than Unit C, firmly
cemented by clay and iron oxide, massive; no
sharp contact with Unit C. On weathered
surface the color is much lighter than fresh
cut. Joints filled with greenish gray clay
A Yellow brown and greenish gray, slightly
sandy, silty, massive clay, that weathers
blocky, sharp contact with Unit C that lies
above __._ ....

Locality LJf-2N-7E-6 dc: On the east side of
Highway 146.

Unit

Description

th

D Weathered Zone
Fine to very coarse, angular to subrounded
quartz sand, most of clay has been leached out,
some limonite forming along contact with Unit C
C Fine to very coarse, angular to subrounded,
quartz sand, some pea-size gravel scattered
throughout unit, mottled light and dark red
brown, yellow-brown, greenish gray on east end
of unit, cemented with iron oxide and clay,
contains thin crossbedded laminae, sharp contact
with Unit B, resistant to weathering ---

Up to 13.0

Up to 14.0

Up to 5.5

Florida State

Variable
sickness (feet)

3.0-9-3

60 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

B Mottled light yellow-brown and greenish
gray, slightly sandy, waxy, blocky, massive, clay,
sharp contact with Units A and C ---- 1.5
A Light yellow-brown, fine to very coarse,
angular to subrounded, quartz sand, cemented
with iron oxide and clay, contains laminae of
white clay (0.5-2mm) that are crossbedded, sharp
contact with Unit B. Pea gravel scattered
throughout unit. At top of unit is a thin bed
that is resistant to weathering ------3.4

Locality LJf-2N-6E-1 dd: On north side of State Highway 146.
Upper Miocene vertebrate remains were found at this locality;

Unit Description Variable
thickness (feet)

F Very fine to coarse, predominantly light
yellow and red brown, very silty and clayey,
quartz sand, massive bedding, gradational contact
with Unit E, but more clayey. Roadcut slopes
back and near the top of unit the sediments
become a highly weathered yellow tan with much
of the clay leached away ___------- __ 7.5
E Very fine to medium, some coarse mottled
light brown and grayish green, angular to sub-
angular, quartz sand cemented with iron oxide
and clay, thin green laminae of clay, ?cross-
bedded, gradational contact with Unit F, but
fairly sharp contact with Unit D, weathers
irregular, forms a slight bluff _------ 2.0
D Dark yellow-brown, silty, sandy, waxy,
massive clay, fairly sharp contact with bed
below; most of unit covered but to the east it
thickens and becomes a dark gray, pale olive
color, similar to Unit B _--------- -- 1.5

pebbles, clayey, contains blebs of yellow brown
clay and light gray clay granules; contact with
the underlying clay Unit B fairly sharp. Unit C
upon exposure to weathering becomes sufficiently
lithified to form a small wall along the side of the
roadcut. On the west end of the outcrop, the
unit thickens and remains resistant to weather-
ing. This unit contains vertebrate remains ------__ 2.0
B Pale olive, waxy, blocky, sandy, clay, fairly
sharp contact with Unit A, unit slopes back along
roadcut, a rubble of light gray, very fine grained
sandstone on the surface of this unit occurs,
which forms a cellular-like structure ---_______ 4.0
A Pale olive to white and yellow-brown, very
fine to medium, some coarse, angular to sub-
angular, quartz sand cemented with silica and
clay, very clayey, massive, the outer surface of
this unit is case-hardened and forms a thin
sandstone layer just on the surface that is very
resistant to weathering ___--___ ---_._.....__--------..... 3.0

QUATERNARY SYSTEM

Pleistocene and Recent Deposits

Distribution.-Surficial sediments of Jefferson County from the
Cody Scarp near Wacissa to the Gulf of Mexico form the Gulf
Coastal Lowlands and are Pleistocene in age. The Recent
sediments are confined mostly to the present stream valleys.
Northwest of Wacissa, Pleistocene deposits make up a series of
sand hills.
General Lithology.-The Pleistocene deposits forming the Gulf
Coastal Lowlands south of the Cody Scarp are very fine to medium
quartz sands with blue-green to light olive montmorillonitic clay
lenses. The clay lenses contain occasional very badly weathered
macrofossils. In the sandhill area the sediments are yellow-brown,
very fine to very course, predominantly fine to medium, angular
to subrounded, clayey, quartz sands.
The Recent deposits occurring along the stream valleys are
reworked Pleistocene quartz sands and quartz sands derived
from the Miccosukee Formation.

62 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

Thickness.-Geologic cross section A-A' (fig. 14) shows that the
Pleistocene deposits range in thickness from 2 to 3 feet at the
coastline up to 20 feet at the toe of the Cody Scarp. Cross section
D-D' (fig. 14) shows that at the Jefferson-Wakulla County line the
Pleistocene is about 7 feet thick. Eastward it thins to only a
veneer but at the eastern edge of the county the Pleistocene sands
thicken to approximately 10 feet.
In WJf-2S-3E-31-ca and WJf-1S-3E-3-ca located on the western
edge of the county, 20 and 37 feet of Pleistocene quartz sand,
respectively, overlie the St. Marks Formation.

Stratigraphic Relationships.-The Pleistocene deposits uncon-
formably overlie the St. Marks Formation and the Suwannee
Limestone in the southern part of the county. In the sandhill area
northwest of Wacissa, Pleistocene sands unconformably overlie
the Miccosukee Formation.

Fauna.-Vertebrate remains have been found in the Aucilla River
and S. J. Olsen (personal communication, January 8, 1964),
remarked that "the general clear waters of the Aucilla River have
been particularly rewarding for the skindiving bone collector.
From the eroded holes in the bottom of the river bed, along its
entire course, countless bones of late Pleistocene and sub-Recent
mammals have been collected. These remains appear to be
redeposited, and, in some cases, entombed in a reworked clay."
Some of the forms represent animals still found in the area
(deer, bear) however, the bulk of the mammals are of genera that
become extinct before the close of the Pleistocene."
"Perhaps the most important find is one of associated Bison
bison (the modern plains "Buffalo") with the remains of the
extinct long-horned bison, Bison cf. latifrons. Most mammalogists,
in past reports, do not map the distribution of the plains bison
as extending into Florida, although the Spaniards reported the
animals in the vicinity of Lake Jackson in Leon County."
"Credit for collecting representative bones of the animals listed
below goes to Mr. Richard Ohmes and his son Donald, of Chaires,
Florida. The bones were recovered by scuba diving and are in
the Ohmes' collection in Chaires."

The configuration and altitude of the Suwannee Limestone is
shown by a contour map (fig. 10). The geologic cross-sections in
figure 14 further exemplify the altitude of the beds. The contour
map was constructed from information gathered by studying
well cuttings and gamma ray logs.
As indicated on the contour map, the top of the Suwannee
Limestone is very irregular as a result of erosion. The contour
lines are generalized and can not possibly show all the irregularities
of the limestone surface. The map shows that two positive and

64 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

several negative areas are present. The positive areas may be
related to the northwest trend of the Ocala Uplift (Vernon, 1951,
p. 48). The two negative areas on the western side of the county
could be related to the deep basin known as the Apalachicola
Embayment of the north Gulf Coast sedimentary province
(Pressler, 1947, p. 1853). The geologic cross sections (fig. 14)
indicate the basins were active after Suwannee times. The basin
developed on the east side of the county is deeper and appears
to be smaller than the one mentioned above. The western side
of the high located in the central and eastern side of Jefferson
County could be interpreted as faulting based on the linear
alignment of the contour lines. However, the writer chose not to
draw in a fault along this trend, as subsurface data is lacking.
Also the contour map may be drawn on an eroded surface and
therefore, not a true representative of the structural conditions.
The high area located north of Lamont was drawn on the basis
of one outcrop and may represent an area that was once connected
to the positive area in the central part of the county, but has been
separated by erosion.
Establishing true dip and strike of the Suwannee Limestone
would be difficult and would depend largely in what section of the
county you were working.

GEOLOGIC HISTORY

The relative age of the deposits in Jefferson County range in
age from Recent to Paleozoic. The rocks are either exposed or have
been penetrated in the subsurface by wells.
From the beginning of late Cretaceous, until early middle
Eocene, Jefferson County was in an area of plastic deposition.
At the beginning of early middle Eocene the depositional environ-
ment changed and carbonates became the predominant sediment
deposited.
During this period of time the middle Eocene, Lake City
Limestone, the Eocene Ocala Group, and the Oligocene Suwannee
Limestone was deposited. The above formations represent a
depositional change from clastics to carbonates that were deposited
in a shallow, warm open sea. At the end of the deposition of the
Lake City, the early middle Eocene seas regressed and according
to Vernon (1951, p. 92), the Avon Park Limestone was deposited
by a transgressing sea on the eroded surface of the Lake City
Limestone. The end of Avon Park deposition again marked the

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

regression of the seas and its surface emerged and was eroded.
The seas once again returned and the Ocala Group was deposited
unconformably upon the Avon Park Limestone. During the time
the upper Eocene Ocala Group was deposited the seas did not re-
gress, as there does not appear to be any break in deposition be-
tween the formations of the Ocala Group. The Eocene Epoch was
brought to a close with the deposition of the Crystal River, the
youngest formation in the Ocala Group.
The lithology and fauna of the Oligocene Suwannee Limestone
seems to indicate that it was deposited in seas that were warm,
shallow and open. At the close of the Oligocene Epoch a period
of predominantly plastic sedimentation took place. The two
positive areas shown on the contour map (fig. 10) may be related
to the Ocala Uplift, a post-Oligocene structural movement, (Vernon
1951( p. 61-62). These areas were not, however, high enough
to prevent encroachment by the early Miocene seas that deposited
the St. Marks Formation. As the cross-sections in figure 14 show,
the St. Marks Formation was deposited on top of the high areas.
The basin on the western side of Jefferson County appears to have
been formed prior to the encroachment of the early Miocene seas.
However, the thick deposits of St. Marks in the basin seems to
indicate that subsidence was still taking place up to the close of
early Miocene. As shown by the sediments forming the St. Marks
Formation, the same influence of carbon deposition was occurring
during early Miocene, even though sands and clays were being
deposited with the carbonates.
At the end of early Miocene time extensive erosion took place
in Jefferson County, especially in the eastern part, where the St.
Marks is either missing or very thin and the Hawthorn Formation
lies directly upon the Suwannee Limestone.
During Middle Miocene time, the depositional environment
changed and a great mass of clastics generally masked out all
carbonate deposition. The shallow marine or brackish water
deposits composing the Middle Miocene Hawthorn Formation
consists of sands and clays that contain phosphorite. As the
deposition of the Hawthorn deposits ceased, a predominantly
marine depositional environment gave way to a deltaic environ-
ment. The deposits forming the delta complex are widespread
as they encompass many square miles both to the east and west
of Jefferson County. The age of these deposits, at least in part,
has been established as late Miocene on the basis of land
mammals found in eastern Jefferson County. The sequence of

66 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

deposition from Middle Miocene Hawthorn Formation to the
overlying Upper Miocene Miccosukee Formation gives the appear-
ance of being only a gradual change in the mode and environment
of deposition and the contact is probably a conformable one.
With the inception of the Pleistocene Epoch, the seas once
again stood over Jefferson County at various levels and formed
the Gulf Coastal Lowlands in the southern part of the county.
The Aucilla\River and most of the creeks probably had their
beginning during the Pleistocene Epoch and the St. Marks
Formation was almost entirely removed by erosion in the Gulf
Coastal Lowlands.
Since the beginning of the Recent Epoch, sea level has been
fairly stationary and the deposition of sediments in Jefferson
County is restricted to alluvium along the many streams, peat and
muck in the lakes and Coastal Marshes.

THE MYTH OF THE WAKULLA VOLCANO

Articles by Wilfred T. Neill (1963) and Hallie Boyles (1964)
have been recently published on a volcano in the southern part
of Jefferson County. The following general information was taken
from these two articles.
Superstition, folklore and imagination produced strange tales
about a thin column of smoke and sometimes fire that rose above
the swamps near the Wacissa River, in southern Jefferson County.
According to Indian legend the column of smoke had always
been there.
Supposedly, the Spaniards were the next people after the
Indians to see the smoke.
Undoubtedly, as they and other people in later years watched
the smoke curling up out of the swamp week after week and year
after year, they begun to speculate about its origin.
As the story goes the Spaniards thought perhaps the smoke
was coming from a pirates den.
When St. Marks began to develop as a seaport, sailors used
the smoke column to get their bearings as they approached the
coast. They are said to have remarked that the old man of the
swamp was smoking his pipe again.
Prior to civil war days the local folks thought perhaps the
smoke was coming from a camp of run away slaves.
Finally someone advanced the theory that the smoke was from
a volcano. As the story of the volcano began to spread, historians,
newspapermen, writers, and just plain folks came from far and

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

wide to investigate the strange phenomena. In fact, a New York
newspaper man lost his life trying to solve the mystery.
The smoke coming from the Wacissa Swamp seemed to be
located near the small settlement of Wakulla and was named the
"Wakulla Volcano" by Barton Jones in an article published in the
Lippincott's magazine in 1882.
Maurice Thompson, in his novel "The Tallahassee Girl," wrote
about the great smoke column. He remarked that the smoke column
was no hoax and would be a permanent and persistent mystery.
On August 31, 1886, an intense earthquake rocked the city of
Charleston, South Carolina. The earthquake was intense enough
that shock waves were felt in Tallahassee. The interesting thing
about this is that on this day the smoke disappeared, never to be
seen again.
Consequently, many of the local residents attribute the
disappearance of the volcano to the Charleston earthquake.
In recent years several eye witnesses claim they have seen the
crater. According to their reports, huge black boulders charred
by fire surround the crater.
However, evidence gathered by the Division of Geology
indicates that the surface rocks in Jefferson County are far
different from those that come from volcanoes. Volcanic rocks
are present in the county, but lie below 7000 feet of sands, clays
and limestones. These volcanic rocks form what geologists call
volcanic diabase sills or dikes and are believed to be millions of
years old. Since the time the sills or dikes were formed the rocks
show no evidence of volcanic activity in the area.
The reported smoke coming from the Wacissa Swamp presents
a problem, although not an uncommon one. In an article in Florida
Wildlife about the volcano Wilfred Neill presents the theory that
the smoke was a result of peat fires that varied in intensity. He
further states that the earthquake of 1886 caused sinkhole
development in the area and subsequently the burning peat slumped
into these collapse features and was extinguished. Whether or
not Mr. Neill is correct in his assumptions, his explanation is a
reasonable one.
The large boulders supposedly of volcanic origin are nothing
more than silicified limestone residue of the Suwannee Limestone.
They represent the remains of a highly eroded limestone surface
where the original composition of the rock has been replaced
chemically by quartz. These boulders in no way are related to
volcanic activity.

68 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

The volcano story makes for interesting popular reading, but
cannot be substantiated by any fact, and therefore, is nothing
more than a legend or a myth.

ECONOMIC GEOLOGY

LIMESTONE

The term limestone applies to a sedimentary rock composed
essentially of calcium carbonate (CaCOj). It may have varying
amounts of impurities such as clay, silica, iron oxide, carbonaceous
material and magnesium carbonate.
The quantity of limestone in Jefferson County is sufficient to
sustain large quarry operations. The Suwannee Limestone is the
most important source of limestone because of its accessibility,
softness, and as shown in table 5, it is essentially a pure "high
calcium" rock in that it contains more than 95 percent calcium
carbonate. The distribution of the Suwannee Limestone is shown

1The percentage total is the sum of all the percentages of the individual chemical components
and do not always add up to 100 percent. To convert the sum of all the components to 100
percent use the following formula:
Chemical component x 100
percent total

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

on figure 20. In 1964, the only active mining of limestone was
by the Jefferson County Road Department and Buckeye Cellulose
Company for use as road metal in the southern part of the county.
In adjacent Taylor County, limestone has been quarried for
use as a road base. In both cases, the method of mining has been
with draglines and front end loaders on tractors.
The abundance of Suwannee Limestone could make it a very
valuable commodity for use in road building as a base course
material and stabilized base rock. A number of samples were
submitted to the State Road Department to see if they would
meet their specifications for use as stabilized base rock and base
course material and, as noted on table 6, all categories were
satisfactory.
The high calcium content of the Suwannee Limestone would
make it very suitable for use in any chemical process such as
agricultural limestone and the manufacture of cement, and quick
and hydrated lime.
Reves (1961) presented a discussion of the various uses and
technical data pertaining to uses of limestone.
Some of the main factors involving the future exploitation
of the limestone resources in Jefferson County are transportation
and fuel. At present no railroads traverse the area where the
greatest reserves of limestone occur. However, two major railroads
run through the county and spur lines could be extended into this
region. Two principal highways, U. S. Highway 90 and U. S.
Highway 27, and several Florida secondary highways run
sufficiently near the limestone deposits to be useful for transporting
the commodity to local consumers or to rail lines for shipping.
Upon the completion of Interstate Highway 10, figure 21, across
Jefferson County another important transportation route will
become available.
Upon the construction and completion of the intercoastal
waterway (fig. 21) off the coast of Jefferson County, another
means of transportation would become available and open the way
to markets all over the State.
A natural gas pipeline traverses the county (fig. 21) and could
be an important source of fuel in potential chemical processing
of limestone.

DOLOMITE ROCK

Secondary dolomite generally is considered a variety of
limestone that theoretically contains 54.6 percent calcium

70 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

G E 0

1 0 1 2 3 45 MILES
SCALE

L-- c lie e B1
of A r IE.1-1c

STATE BOARD of CONSERVATION

EXPLANATION

LIMESTONE
high calcium, soft, friable

DOLOMITE

Primary Area of
SClayey Quartz Sand

_ Secondary Areas of
Clayey Quartz Sands

prepared by DIVISION of GEOLOGY

Figure 20. Distribution of the economic deposits of Jefferson County, Florida.

carbonate (CaCO3) and 45.4 percent magnesium carbonate
(MgCO3). This is not to say that all dolomites will approach the
theoretical proportions mentioned above for there is generally
gradations from dolomitic limestones, (4.4 to 22.7% MaCOs)
calcitic dolomites, (22.7 to 41.0% MaCO,) to true dolomites (41.0
to 45.4% MaCOS). Dolomites can, in a general way, be
distinguished from limestones by their slower effervescence in

cold, dilute, hydrochloric acid. This test does not, however, tell
you the amount of magnesium carbonate present.
The dolomites of commercial value in Jefferson County are
Suwannee Limestones that have been replaced in part by MgCO3.
The approximate areal distribution of the dolomites is shown on
the mineral resources map (fig. 20). Field observation seems to
indicate that the dolomites are confined for the most part along
the Aucilla River and the low area east of the Aucilla River and
south of U. S. Highway 98. The thickness of the dolomites in
this area is not known; however, core test WJf-4S-3E-24-bd
bottomed in dolomite at 24 feet. Along the Aucilla River in Taylor
County, dolomite prospecting was conducted by the Florida
Geological Survey in 1942. For results of these test holes, the
location of the wells and the dolomitic areas, the reader is referred
to the Florida Geological Survey Report of Investigations No. 3,
p. 13-25. Observation of table 7 shows that the dolomites tested
are almost pure as they contain 41 toA2 percent magnesium
carbonate. One of the samples, LJf-3S-4E-10-dc was subjected
to the Los Angeles abrasion test and failed as its abrasion loss
was 46 percent and exceeded the 40 percent minimum set by the
Florida State Road Department Standard Specifications.

CLAY DEPOSITS

INTRODUCTION

At the present time there is no clay being mined commercially
in Jefferson County. The clays are montmorillonites and kaolinites
which occur in the Hawthorn, Miccosukee, and the Pleistocene
deposits. Some of the clays in the Miccosukee Formation have
a very small percentage of sand and may be of commercial value.
However, because of their lenticular nature and generally short
lateral extent, an extensive drilling program would be necessary
to determine if it would be feasible to mine them for commerical
use. In the southern part of the county the terrace deposits contain
sandy montmorillonitic clays and detailed exploration may find
deposits suitable for commercial use.

TESTS

Samples of clays from outcrops were collected and submitted
to the Bureau of Mines for determination of the physical and firing
characteristics and recommended uses. Table 8 gives the data on

1The percentage total is the Sum of all the percentages of the individual chemical components and do not always add up to 100
the sum of all the components to 100 percent use the following formula:
Chemical component x 100

percent total

percent. To convert

Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace

74 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

these clays. Also included in the table is an analysis of clay
collected from a 111/2 foot test hole, located one and one-half miles
east of Wacissa near milepost 822 on the abandoned Seaboard
Air Line Railway. The data on the clay from the test hole was
taken from the Florida Geological Survey Information Circular
No. 2, (1949, p. 35, 54).
The location and description of the samples collected and tested
as shown in table 8 are as follows:

The most extensive areas of sand occur in the Gulf Coastal
Lowlands, along the eastern side of the county, the Dune Belt and
in the sandhill area northwest of Wacissa (fig. 20). In the Gulf
Coastal Lowlands area the sand deposits are generally thin,
slightly clayey, fine to medium grained quartz. The deposits in
the Dune Belt sandhill area are very fine to very coarse grained,
predominantly fine to medium grained, clayey, iron-stained quartz
sand. Coarse sands were encountered in core holes WJf-1S-3E-
13-aa from 35 to 60' and in WJf-1N-6E-8-dd located in the eastern
part of the county, from 16 to 43 feet. The sands in the core
holes, and in the Dune Belt, would require some washing to remove
the clay content.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

PETROLEUM POSSIBILITY

Two oil test wells, the Southern States Oil Corporation No. 1
Millard and Gossard and the Coastal Petroleum Company No. 1
E. P. Larsh, have been drilled in Jefferson County. The two tests
penetrated the Atkinson Formation of Upper Cretaceous age,
which is the same age and is similar lithologically to the oil pro-
ducing zones in the Pollard Field just north of the Florida-Alabama
State line in Escambia County, Alabama. Neither of the tests had
oil shows and were abandoned as dry holes. Although the absence
of oil in these wells has been discouraging, the sands in the lower
member of the Atkinson Formation appear to be adequate as a
reservoir rock and if oil is present in the county these beds are
the best prospect.

PHOSPHATE

Phosphate is common in the Hawthorn Formation in Jefferson
County. The phosphate occurs in two forms, as phosphorite and
as colloidal phosphate embedded in a clay matrix.
A thick section of colloidal phosphate-clay was found in a core
hole located in the center of Sec. 5, T2N, R5E and is the richest
phosphate deposit encountered in the county. Nodular beds of
phosphate and phosphate pebbles up to 2 inches in diameter also
occur within the unit.
The phosphatic unit was analyzed for PsO, and the results of
the analyses are listed below:

Light color,
some cracking,
shrinkage a
little high,
addition of
alkali might
make a pottery
or derative tile

Color:
950* C
10500 C
10900 C
11500 C
11900 C
12500 C

Porosity %:
9500 C
10500 C
10900 C
11500 C
1190 C
12500 C

Potential Use:

Reddish Orange
Reddish Orange
Brick Red
Brick Red
Brick Red
Brick Red

34.8
35.0
34.0
34.0
32.5
33.3

Rather porous,
common brick

I

78 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

971/2-100 8.9
100-1021/2 9.2
1021/2-105 13.7
105-1071/ 11.9
10712-110 12.8
110-1121/2 6.9
1121/2-115 6.9
115-1171/2 3.9
11712-120 11.2
120-122/2 7.6
1221/2-125 6.9
125-1271/2 11.2
1271/2-130 8.3
As shown by the analysis, the phosphate content of the core
hole interval is low. However, in future years a lower grade
phosphate may be economically acceptable and could be utilized
as suggested by Vernon (1951, p. 228-30). He (Vernon, 1951,
p. 228-30) indicates that this type phosphate is used as a soil
conditioner and filler in fertilizer.
The Hawthorn Formation in Jefferson County also contains
sand size phosphate particles that are associated with clayey
sands or sandy montmorillonitic clays. These particles are
referred to in this report as phosphorite. The visual estimate of
the phosphorite grains in cuttings from wells, core hole samples
and outcrops indicates the phosphorite does not exceed 10 percent
of the bulk volume of the sediments. Vernon (1951, p. 224) reports
that phosphorite from other areas in Florida is composed of the
mineral fluorapatite.
Knowledge of the occurrence of phosphate in Jefferson County
is limited to the available data and trends cannot be predicted
at this time. However, in the future as more is known of the
genesis and occurrence of phosphate, these data may indicate that
further investigation is warranted.

GROUND WATER

The term "ground water" refers to the water that fills all
the open pores and interstices in the rocks below the surface of
the earth in the zone of saturation.
The source of ground water in Jefferson County is the
precipitation in the county and nearby areas. Some of the
precipitation that falls on Jefferson County leaves the area by

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

surface runoff in streams, by evaporation and by transpiration.
The part that is left soaks into the ground and slowly moves
downward to the zone of saturation. After reaching the zone of
saturation, the water under the influence of gravity begins to move
slowly toward points of discharge such as wells, springs, streams,
or the Gulf of Mexico.
Ground water in Jefferson County can be divided into two
categories: (1) Unconfined water (water table) which occurs in
the shallow formations above the St. Marks Formation and is
under atmospheric conditions; that is, the water surface is free
to rise and fall. The unconfined water will not be discussed in
this report. (2) Water that is confined under pressure between
relatively impermeable formations, and is not free to rise and
fall. This water is said to be under artesian conditions.

ARTESIAN WATER

The artesian water in Jefferson County occurs in the Floridan
aquifer from which most of the water for irrigation, industry,
and public supply is derived.

FLORIDAN AQUIFER

The term Floridan aquifer was introduced by Parker and
others (1955, p. 188) and it includes all or parts of formations
from Middle Eocene to Middle Miocene.
In Jefferson County it is believed that the Floridan aquifer is
recharged by Lake Miccosukee through sinkholes, along the Aucilla
River, and in the northeastern portion of the county in the swamp
areas where leakage occurs through the overlying sediments of
the Hawthorn Formation and Miccosukee Formation.

FLUCTUATIONS OF WATER LEVELS

Twenty-one wells were measured periodically from January,
1960, to December, 1962, to determine trends in water-level
fluctuations. Water-level recorders were installed on two wells in
April, 1960, and were in operation until December, 1962. The
graphs obtained from the water-level recorders showed a daily
as well as seasonal fluctuation.
To determine the relationship of rainfall to water levels, a
cumulative departure curve of average precipitation at Monticello
from 1948 to December, 1962, was plotted, figure 22. Except for

CUMULATIVE DEPARTURE FROM THE AVERAGE PRECIPITATION
20 BASED ON ANNUAL AVERAGE OF 54.82 INCHES

Figure 22. Cumulative departure curve of average precipitation at Monti-
cello, Jefferson County from 1948 to December, 1962.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

1952, the rainfall was below average between 1948 and 1956. In
1957 the rainfall was sufficient to start an upward trend which
peaked in December, 1960, 12 inches above normal. From
December, 1960, through December, 1962, the cumulative
departure curve shows a gradual decline.
The hydrograph of wells WJf-3N-4E-22-cb, WJf-3N-7E-27-bb,
WJf-1S-3E-15-dc, and WJf-1S-4E-28-ac and the average monthly
precipitation graph for the years 1960 through 1962 are shown
on figure 23. As shown in the figure, the hydrographs indicate
that during the months of high precipitation, the water levels
rise and during the months of low precipitation, the water levels
fall. The peaks on the hydrograph of well WJf-1S-4E-28-ac
indicate rapid response of the water level to heavy rainfall near
the well. The overall trend of the water levels from July, 1961,
to December, 1962, has been downward.
In well WJf-3N-4E-22-cb, the water levels declined 8.88 feet
from May, 1960, to December, 1962, and the water level in well
WJf-1S-3E-15-cd declined 3.92 feet during the same period.
The principal cause of fluctuations of water levels in Jefferson
County is believed to be rainfall, as very little water is withdrawn
from the aquifer.

PIEZOMETRIC SURFACE

The height to which water will rise in tightly cased wells that
penetrate an artesian aquifer creates an imaginary surface called
the piezometric surface. It should be pointed out, however, that
in parts of Jefferson County, the piezometric surface lies below
the top of the bedrock forming the Floridan aquifer. This condition
indicates that in these areas the ground water is actually under
water table conditions rather than artesian.
Two maps, figures 24 and 25, were prepared to show the
configuration of the piezometric surface in May, 1960, and in
December, 1962. The primary reason for showing the piezometric
surface at these two different time intervals was to point out how
the artesian pressures had dropped during this period. From
May, 1960, to December, 1962, the amount of decline was about
9 feet in the northern half of the county and 3 feet over most
of the southern half of the county. This lowering is probably the
result of the decline in rainfall after 1960.
The piezometric surface ranges from sea level along the coast
to 80 feet above sea level in northeastern Jefferson County. The

EXPLANATION
037
WELL NUMBER IS ALTITUDE OF THE PIEZOMETRIC
SURFACE IN MAY 1960.

CONTOUR SHOWING THE ALTITUDE OF THE
PIEZOMETRIC SURFACE IN FEET.
CONTOUR INTERVAL IS 10 FEET
DATUM IS SEA LEVEL.

R5 E

R6 E

R7E

Figure 24. Jefferson County, Florida, showing the piezometric surface of
the Floridan aquifer in May, 1960.

R3 E

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R7E

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84 FLORIDA GEOLOGICAL SURVEY-BULLETIN FORTY-EIGHT

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EXPLANATION
036
WELL NUMBER IS ALTITUDE OF THE PIEZOMETRIC
SURFACE IN DECEMBER 1962.

CONTOUR SHOWING THE ALTITUDE OF THE
PIEZOMETRIC SURFACE IN FEET.
CONTOUR INTERVAL IS 10 FEET.

DATUM IS SEA LEVEL.

R5 E

R6 E

R7E

Figure 25. Jefferson County, Florida, showing the piezometric surface of
the Floridan aquifer in December, 1962.

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

comes up again near Nutall Rise. Another area of recharge is
believed to exist in the northeast part of the county by leakage
through the plastics overlying the Suwannee Limestone.
In well WJf-1N-4E-26-bb the water level is approximately
115 feet higher than the water level in a Floridan aquifer well
located two miles to the north. It is on this basis the writer
believes that water from WJf-1N-4E-26-bb is coming from a
secondary aquifer or that it is a water table well.
The recharge to this aquifer is probably from the overlying
Hawthorn Formation and Miccosukee Formation.
By comparing the hydrograph and the average monthly
precipitation graph for the years 1960 through 1962, figure 26,
the water level seems to respond to rainfall; that is, the water
levels rise during wet periods and fall during dry periods.
WJf-1N-4E-26-bb also shows a downward trend of the water
levels after 1960. The low water level in September, 1960, was a
result of extensive pumping of the well, and at the time the
measurement was made the water level in the well had not
recovered from the pumping.
A complete water analysis was run on a water sample from
well WJf-1N-4E-26-bb and is shown in table 9.

QUALITY OF WATER

The rain falling upon the earth's surface is relatively free of
dissolved minerals except for small quantities of atmospheric
gases and dust. However, that part of rainfall that is absorbed
into the soil and percolates downward through the earth's crust
dissolves a part of the rock with which it comes into contact.
Consequently, the chemical character of the water is to a large
degree dependent upon the composition solubility of the material
through which it has passed.
Chemical analyses of water from wells in Jefferson County
and from well WTy-4S-3E-24-bd in Taylor County were made
by the Quality of Water Branch of the U. S. Geological Survey
(table 9). All of the samples were from the Floridan aquifer,
except one water sample from a secondary aquifer or water table
in Jefferson County. The chemical composition of the seven
samples is shown in figure 27 by bar graphs. The mineral
constituents analyzed are discussed below. The mineral constituents
as shown in table 9 are expressed in parts per million (ppm) by
weight. One part per million (ppm) is equivalent to approximately

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Figure 26. Hydrograph of well WJf-1N-4E-26 bb and a total monthly
precipitation graph of rainfall in Jefferson County, Florida.

The concentration of dissolved solids in water is approximately
equal to the amount of mineral matter left after a quantity of
water is evaporated. The U. S. Public Health Service recommends
that for drinking water the maximum amount of dissolved solids
should not exceed 500 ppm. However, water containing 1,000 ppm
is permissible if water of better quality is not available. The
dissolved solid concentrations in the water samples from Jefferson
County ranged from 112 to 206 ppm. Well WTy-4S-3E-24-bd,
located in Taylor County, had a dissolved solid content of 1,790
ppm.

HARDNESS

In waters that are considered hard, soap does not lather easily
and a curd is left on the surface of the water. The cations, calcium
and magnesium generally are the cause of hardness of water.
The calcium and magnesium hardness of the water samples
analyzed from Jefferson County ranges from 100 to 206 ppm. The
water sample from the well in Taylor County had a calcium and
magnesium hardness of 670.

TEMPERATURE

The temperature of the water from all of the wells ranged
from 68' to 710 F.

SPECIFIC CONDUCTANCE

The specific conductance of water is a measure of its ability
to conduct an electrical current. The higher the mineralization the
better the water conducts an electrical current.
The relationship between the measured total dissolved solids,
hardness and specific conductance of water from six wells located
in Jefferson County is shown by the straight line plots in figure
28. Specific conductance of 18 water samples from wells in
Jefferson County, one from Madison County, and two from Taylor
County, are shown in table 9. An approximate value for the
hardness and total dissolved solids was calculated from the specific

GEOLOGY OF JEFFERSON COUNTY, FLORIDA

Figure 28. Hardness and total dissolved solids curve of artesian water in
Jefferson County, Florida.

conductance of these 18 water samples by using the straight line
plots in figure 28.

HYDROGEN-ION CONCENTRATION (pH)

The concentration of hydrogen-ions in water is expressed as
pH. A water having a pH of 7.0 is said to be neutral. A higher
pH value indicates alkaline water and a lower value is said to be
acidic and may be corrosive. All the water samples tested had a
pH value greater than 7.0 and ranged from 7.9 to 8.4.

SILICA (SiO,)

Silica is dissolved from rocks and is present in almost all
ground water samples. Silica is of little importance in water use
except it can contribute to the formation of scale in steam boilers.
Silica in the 6 samples from the Floridan aquifer range from
7.2 to 17 ppm. In the water sample from the secondary artesian
aquifer the silica content was 39.0 ppm.

IRON (Fe)

Iron is one of the most objectionable constituents occurring
in ground water. The quantity may vary geographically as well
as vertically within the same formation. Iron in excessive
quantities will stain laundry, plumbing fixtures and cause water